Abstract: Based on the monthly sunshine duration data of Beijing and its surrounding stations from 1923 to 2020, the changes of sunshine duration and its future trends in Beijing for the recent 100 years were analyzed by using mathematical statistics methods. The results show that: (1) From 1923 to 2020, the tendency rate of annual sunshine duration decreased significantly in Beijing, with the changing rate (-22.42±12.89) h/10a. Seasonal sunshine duration decreased significantly in summer, autumn and winter. However, the sunshine duration in spring showed an insignificant increasing trend. (2) Significant quasi-periodicity of 56 a and 36 a were detected in the annual sunshine duration of Beijing from 1923 to 2020, and the abrupt change occurred in 2000. (3) In the future, the annual and seasonal sunshine duration in Beijing will remain the same as that in the past. The continuous intensity of sunshine duration is very strong in annual, summer and autumn. However, the intensity in spring and winter are relatively weak.