Abstract: Based on the climate average data of 156 national meteorological stations in Sichuan Province from 1991 to 2020 and from 1981 to 2010, the difference distribution characteristics and business application differences of the two 30-year climate average values are compared and analyzed from the annual and monthly scales. The results show that: (1) In the past 30 years, the annual average temperature in Sichuan Province has increased by 0.3 ℃, the average temperature of each month has increased, and the temperature of 93.7% stations in Sichuan Province has increased by 0.1 ~ 0.5 ℃. (2)In the past 30 years, the average annual precipitation in Sichuan Province has increased by 3.8mm, and the precipitation difference changed greatly from June to October, the annual precipitation in most areas of Western Sichuan Plateau increased, while that in the Basin and Panxi area reduced. (3) After the implementation of the new 30-year climate average, the annual and monthly average temperature anomaly in most areas of Sichuan Province decreased, and the average annual precipitation anomaly in the whole province did not change much, but there were great regional differences in the annual and monthly precipitation anomaly. (4) The average temperature in winter in Sichuan has increased, in the past 42 years, the warm winter has decreased by 6 years and the cold winter has increased by 5 years; In spring, the temperature increased greatly, the start date of spring in the Basin is earlier, and the number of continuous days increased. (5)The change of climate average value has a great impact on the business application of meteorological elements and climate event monitoring and evaluation.