Abstract: Accurate monitoring of the changes of cultivated land irrigation area is of great significance for managing limited agricultural water resources and ensuring food security. Baojixia Irrigation District of Shaanxi Province, a typical irrigation district in arid and semi-arid areas of northwest China, was selected. Landsat satellite data based on GEE cloud platform, on the basis of extracting the range of cultivated land use classification, combined with field sampling points, and based on the actual situation of Baojixia Irrigation District, a method for obtaining historical sample points was proposed. By calcula-ting NDVI, EVI, GCVI, WGI and other indexes as classification parameters, the random forest algorithm was used to identify and extract the irrigated areas of cultivated land in 2010 and 2020. The results show that the irrigated area of cultivated land in Baojixia Irrigation District in 2010 and 2020 are 104 211 hm~2 and 90 174 hm~2, overall accuracy are 91.67% and 95.35%, and Kappa coefficients are 0.832 and 0.907, respectively.