Abstract: Based on the 2m daily maximum and minimum temperature data in Sichuan province from 1990 to 2019, the daily variation characteristics are analyzed. The results show that: (1) The daily variation range of 2m maximum temperature was greater than that of minimum temperature. The area with the largest maximum temperature variation was located in the northeast of Liangshan Prefecture, while that of the minimum temperature was located in the north of Ganzi and Aba Prefectures. (2) Among the four seasons, the daily variation range of the maximum temperature in spring was significantly greater than those in summer, autumn and winter. The daily variation ranges of the minimum temperature in winter and spring were greater than those in summer and autumn. (3) The frequency distributions of the daily variation of maximum and minimum temperature were unimodal, with the peak value of the former being 0~2℃ and the latter being −2~2℃. (4) The annual frequency of the maximum temperature with daily variation exceeding 6℃ was significantly higher than that of the minimum temperature. And the spatial distributions of the two high-frequency regions were consistent with the areas of the largest daily temperature variation.