The data sources of Baidu's search list are different according to different lists: the real-time hot list is automatically generated according to the change rate of keyword search volume, and the specific ranking rules are: the search volume of keywords within 24 hours, relative to the change rate of the search volume in the previous 24 hours; In the eleven lists of Seven Days' Concern, Popular Search, World News, Web Games, Web Game Platform, Travel, Group Buying, Luxury Goods, Food, Cosmetics and Pets, and the four first-class list categories of Entertainment, Events, People and Novels. In the five lists of Online Games, Online Game Operators, 3C Mall, Milk Powder and Household Appliances, as well as the three first-level list categories of automobiles, technology and finance, the search index comes from the professional edition of Baidu Index (marked in the lower right corner of the list), and the ranking method is summarized according to the search volume of different factory goods. Baidu Index Professional Edition is a systematic data service platform for market demand monitoring, competition analysis, crowd insight, advertising and effect evaluation based on Baidu's massive search user behavior and search demand analysis. Its purpose is to meet business needs and create marketing value. Baidu Index Professional Edition highly aggregates keyword data. For example, the data of the brand "IPHONE" in the list of "mobile phone brands" covers the search volume of all mobile phone types and related derivatives of IPHONE.