The conventional estimation of farmland irrigation benefits has only taken economic benefits into consideration, which is unfavourable for dealing well with the correlation of farmland irrigation, ecological environment and economic development. To establish modernized farmland irrigation system, its ecological benefits should be substantially considered. We established a benefit model of climate regulation for farmland irrigation using relevant theories of water balance and energy theory, and then took Shaanxi Province as an example to calculate the climate regulation benefits in different regions from 2008 to 2018 and analyzed the influencing factors. The result show that the climate regulation benefits were greatest in Guanzhong region, but lowest in northern Shaanxi, and the climate regulation benefits per square meter in southern Shaanxi, Guanzhong and northern Shaanxi were 0.011 0 yuan/m3, 0.035 0 yuan/m3 and 0.006 9 yuan/m3, respectively. It is found that the extent of economic development is the key factor influencing the climate regulation benefits, and the farmland climate regulation benefits per square meter in the three typical regions rise with time in general.