The report takes 126 administrative units above prefecture level cities in the whole Yangtze River Economic Belt as samples，and comprehensively analyzes the regional development dynamics of the Yangtze River basin by building a social development index of the Yangtze River Economic Belt，including social undertakings，social security，people’s living standards，and social vitality. Compared with last year，the social development index of the Yangtze River Economic Belt has continued to grow，but the impact of the epidemic is still obvious，so the pace of progress is slower than before. From the perspective of regional gap，the gap between the upstream，middle and downstream is still widening，especially between the upstream and downstream. From the perspective of sub indicators，the development of social undertakings across the Yangtze River Economic Belt is relatively stable，and the development of urban and rural areas is relatively balanced. Although social security undertakings are improving，there is still much room for progress. In general，the three provinces and one city in the lower Yangtze River Delta continue to lead the whole region by a large margin，forming a ladder like fault with the middle and upper reaches. The cities in the upper and middle reaches still lag behind in the field of social security，and further targeted measures need to be taken to promote comprehensive social development.