As a small investor, what do we really get while we buy a stock of a company which never pays a dividend?

Basically, by owning that share, corporate law protects the fact that you own the stated % value of the equity of a company.

Companies decide whether to pay dividends, basically, on what the shareholders want. This means that, basically, if the company has profitable projects that it could use its cash on, it won't pay out dividends, and instead it will invest in itself. If a company has excess cash, it will often pay it out as dividends. As a tiny investor, your vote on the Board of Director selection is meaningless, but corporate law protects you from being cheated out of value by the bigger shareholders, so as long as nothing fishy is going on, that means you can basically 'trust' that the company is being run with the best interests of the shareholders (including you) at heart.

So if a company isn't paying dividends, there is a reason. Maybe it is a junior mining company, and won't pay dividends until it strikes copper at a minesite, and can comfortably produce it without massive capital investment.

Why your share holds value is that under corporate law you own a % of the company. You can't walk up to the gates and point out the door you bought with your $100, but if money goes out to shareholders, you will get a piece of it. This could be from future dividends when the company is ready to pay them, or it could be from bankruptcy (probably you won't get much in this case), or if it gets bought out by a larger company (you would get a cash payout or shares in the larger company, depending on the terms of the agreement), or even under liquidation by choice (which is somewhat common for small private companies, but pretty rare for public companies).

In the meantime, if you have the ability to sell your shares in the company through a public stock exchange, you can 'cash out' your value before that future dividend-type payment occurs. This only has value because of the above - basically someone down the line is getting a cash payment from the company itself, and trust in that fact allows the shares to get traded, even by people who might only buy and sell the shares over the course of a day. Be warned - if a company performs poorly, its stock price will drop, so this is not a guarantee that you will get a profit, or even that you will get any money back.

As a small investor, just own less than millions of company, my right was already represent by some big investor, of course I cannot find out which part of the company really belongs to me.

You don't own any particular bit of the company. You can't go into the factory and say "that machine's mine". Instead, you own a share of the whole company.

While the company became big, return to 1, I still cannot get any part of the company.

You can't ever get any particular bit of the company. The only thing you can do is to sell the shares.

If the company will never pay dividend, the only time I can take part of the company back is while the company go to bankruptcy, maybe can get hundred of stock value or even zero from the company.

You get money by selling your shares. If the company has been reinvesting all its profits, instead of paying dividends, then you hope that your shares are worth more when you sell them than when you bought them.

Suppose there is a company that has 1,000,000 shares and the company is worth $1,000,000. Suppose you have 100 of those shares. You can sell them to somebody for $100.

Suppose the company is well-run and it grows to $10,000,000. Your 100 shares are now worth $1,000. When you sell them, you make a profit.

The other time you may get a payout is if somebody wants to buy the whole company. As a shareholder, they have to buy out your shares.

If the company goes bankrupt, you will probably get nothing. The company is worth $0 and nobody wants your shares because they are worthless. Shareholders are the last in line to get paid out when the company winds up, and all its assets are sold. Everybody else that the company owes money to gets paid first. (If the company has enough money to pay out all its creditors, and still has money left over at the end, then it wasn't bankrupt in the first place.)

It is completely normal to buy things, because, the thing will go up in price, even though, the thing pays absolutely no profits.

• a house^†
• gold
• wheat, oil
• artworks
• Alfa Romeos

The situation you describe is completely, totally, normal.

^† Note too that houses have H U G E expenses, far less "never paying one cent in profit".

To retort your analogy (too long for a comment):

Assume there is a company which really did not have any business, and assume it have very good market so that nobody knows its real business value but anybody believe he did well.

And every year, it can provide an amazing financial report, so everybody like to buy its stock, and the price increased to a very high price. And it did not pay any dividend.

The question is is there any difference for the company with other real company who did not pay dividend from the small investor's view?

Where is this "amazing financial report" coming from? If this is a publicly traded company, the report much be audited to verify its accuracy, so lying is not an option. The results in this "amazing" report must have come from somewhere. It can't easily be fabricated. I'm not saying that fraud never occurs, but I don't think a fraudulent example proves your point.

As the other answers have stated, the financial value of a company is based on either its net assets or the present value of its future cash flows (whichever is greater). The stock represents a percentage of ownership of that value. Yes, if the company does not pay a dividend that value is embedded in the company, so the only other way (besides a merger, acquisition, or liquidation) you can profit from that stock is if someone else buys it from you, hoping that they will eventually get a dividend of get bought out. The price that they buy it for would be based on the current value of the company, so your stock still grows in value as the company grows in value.

If the company will never pay dividend, the only time I can take part of the company back is while the company go to bankruptcy, maybe can get hundred of stock value or even zero from the company.

Not true. The company could get acquired or be part of a merger. The value that you get for your stock should be based on what the company gets acquired for. It ma be in all cash, or in the stock of another company, in which case the same arguments apply. It can also buy back its own stock from you, which again is based on the value of the company.