From the perspective of institutional development，business development and customer development，this report proposes the SP-B-C three-dimension model for measuring the development level of science and technology service industry，and evaluates the development level of science and technology service industry in Yangtze River Economic Belt by using entropy weight method. Based on the evaluation results，spatial Theil index was used for regional difference measurement and structure analysis，coupling and coordination degree model was used for coordinated development state analysis，and geographic detector was used for driving factor analysis and risk area identification. The results show that the development level of science and technology service industry in provinces and cities of the Yangtze River Economic Belt shows a steady upward trend in time series and a spatial gradient pattern of high east and low west. The development level difference in the Yangtze River Economic Belt is smaller than the national level，and shows a downward trend. The interval difference between upper，middle and lower reaches is the main reason for the development imbalance. Judging from the SP-B-C coupling，the coordinated development level of science and technology service industry in the Yangtze River Economic Belt has been constantly improved，with Shanghai，Jiangsu and Zhejiang having higher coordination level. Factor detection and interaction detection show that the driving factors of the development of science and technology service industry in the Yangtze River Economic Belt from strong to weak are Intensity of innovation activities，human capital，level of economic development，industrial structure，economic openness，government support. And the pin-two interaction of these driving factors is double-factor enhancement. The risk detection shows that the risk areas are mainly concentrated in the middle and upper reaches.