As a comprehensive index reflecting the dynamic operation of stock market，stock index，called a barometer of national economic development，serves as a significant reference standard for investors at home and abroad to invest in securities and is an indispensible composition of securities financial information service. From the different angels of the stock exchange，the securities company and the third party platform，this chapter analyzes the methods of complying the stock index，the selection of the sample stock，the object of the index service and the market pattern of stock index in China. What's more，we discuss the several development achievements in ecological chain of index chain，product innovation and influences of markets. Finally major developing features of stock index service market are pointed out in China.