In order to improve the quality of information in the securities market and to standardize the information on industry classification of listed companies, the China Securities Regulatory Commission (CSRC) has published the Guidelines on Industry Classification of Listed Companies. It should be said that the "Guidelines" on the classification of listed companies than the original two exchanges of the industry more detailed, and reference and reference to the National Bureau of Statistics, the United Nations International Industrial Classification, the North American Industrial Classification Standards and Morgan Stanley Global Industry Classification and other domestic and international authoritative industry classification standards. However, many securities industry professionals believe that the classification results announced by the two exchanges are still questionable. According to the provisions of the Guidelines, the principle and method of classification of listed companies is to take the operating income of listed companies as the classification standard. When the proportion of operating income from a certain type of business is greater than or equal to 50%, the company will be categorized into the corresponding category of that business. When the company does not have a type of business income proportion greater than or equal to 50%, if a type of business income proportion than the proportion of other business income are 30% higher than the proportion of the company will be classified into this type of business corresponding to the industry category.