Abstract: In order to objectively and comprehensively evaluate the air quality of each city in China and formulate effective prevention and control measures, the six indexes of SO₂,NO₂,PM10,O₃,CO and PM2.5 were selected as evaluation factors, and entropy weight method was adopted to empower each index. Combined with TOPSIS method, the air quality evaluation model was established, and the air quality ranking of 20 major cities was obtained. The results showed that the three major pollutants were SO₂,CO and PM2.5, and the air quality of Shenzhen, Ningbo and Shanghai was better than others. In view of pollution, some suggestions for reducing carbon emissions, popularizing clean energy, strengthening protection measures, paying attention to environmental protection publicity and strengthening supervision mechanism were put forward.

Key words: entropy weight TOPSIS method, city, air quality, evaluation