Based on the survey of the aerial seeding result and the meteorological elements from 1996 to 2005 in the aerial seeding area(take Xunxi county,Chunhua county,Liquan county as examples)of Xianyang,the regression analysis for the effects of the aerial seeding and meteorological elements has been done and the dominant elements affecting the aerial seeding effects has been found out.As a result,the optimum seeding time for aerial seeding in Xianyang is given.