Abstract: The stock market plays a significant role in the country's economy.there're two main functions for a marketing economic country:enterprise financing and optimize resource allocation.for china,serving for the reform of national owned firm ,it's the third function.For achieving those functions,it must do some research in the internal value of the stock.we revealed the theoretical source of the internal value of the firm in this article, and discussed several main models of appraising the internal value of the stock.