Based on the analysis method of the social development index of the Yangtze River Economic Belt in previous years，the report comprehensively evaluates the development effectiveness of 126 cities in the four fields of social undertakings，social security，social balance and social vitality in the whole region of the Yangtze River economic belt by expanding the number of samples and improving the analysis framework. Overall，the social development index of 126 cities in the Yangtze River economic belt has improved compared with previous years，but the score level still has great room to improve，and the regional gap has not been significantly reduced. From the perspective of sub indicators，the urban and rural development of the Yangtze River economic belt is relatively balanced，the development of social undertakings is relatively good，and there is still much room for improvement in social security undertakings. The report lists the benchmark cities in the four areas of social development of the Yangtze River economic belt，and further compares the development of the social fields of 14 important node cities. It is found that the development of the four social fields of Shanghai，Hangzhou and Suzhou is relatively balanced，and some cities still lag significantly in the subdivided areas of social development，so targeted measures need to be further taken to promote the all-round development of society.