Abstract: Based on the observation data of haze days at 44 meteorological stations in Chengdu Plain Economic Zone from 1981 to 2018, the temporal and spatial evolution characteristics of haze days in the region were analyzed, and the regional air quality was quantitatively analyzed by using the comprehensive evaluation model paradigm of urban agglomeration haze days. The results show that : (1) The high haze days in Chengdu Plain Economic Zone were mostly concentrated in Deyang, Chengdu and Leshan and other urban areas. The haze days were the most in winter, followed by spring and autumn, and the least in summer. (2) The high incidence stage of haze days in Chengdu Plain Economic Zone was from 1991 to 2000, and it showed a significant downward trend from 2011 to 2018. (3) Empirical Orthogonal Function (EOF) and wavelet analysis showed that the number of haze days in Chengdu Plain Economic Zone showed a significant downward trend, and the fastest decline occurred in Ziyang, Chengdu and Suining, and a slight upward trend only occurred in northern Mianyang.