The intercepted precipitation and its variation of the canopy of Pinus tabulaeformis and Populus davidiana of 25 years old have been studied.The conclusion shows that the intercepted precipitation of Pinus tabulae-formis and Popular davidiana are 95,2mm and 73.4mm,accounting for 19.6and 14.700 of yearty total ramfall respectively; Intercepted rainfall is78mm and 71.lmm, accounting for 17.40o and 15,500 of rainfall; Intercepted snow is 17.2mm and 2,3mm,accounting for 45.1%and 5.900 of snowfall.The intercepted amount of the canopy changes with different seasons,In summer, the intercepted amount is 51mm,15.8} of the annual rainfall.In spring and winter,Pinus tabulaeformis intercepted amount is low, and intercepted rate is high, Also, both of them in Populus davidians are low, The interceptive process of the canopy is divided into three stages as intercepting,falling raindrop and saturating,The function between the accumulated interceptation and precipitation presents I=ap^b.