Abstract: In order to optimize the living environment of walnut trees and improve the yield of walnut,the16-year-old evacuated stratified walnut cultivar"Wen 185"at full fruit stage was used as the research material in the experiment.Two kinds of microbial agents,i.e.,‘Live’and‘Yeliqin’,were sprayed on the leaves at the key growth stages of walnut at the flower bud differentiation stage,hard kernel stage and seed kernel filling stage,and water was used as the control.In the same walnut orchard,200 times（S1）,400 times（S2）and600 times（S3）of the same concentration of‘Live’and‘Yeliqin’microbial agents were sprayed on the same day,respectively,and three replicates were set.The appearance quality and yield of walnut fruit were determined after harvest,and the results were comprehensively evaluated by membership function to obtain the most suitable application concentration of microbial agents.The results showed that S1 treatment had the highest walnut yield and kernel rate,which were 4 322.4 kg·hm^-2 and 55.12%,respectively.The shell thickness of S1 treatment was the thinnest,which was 1.13 mm,and effectively reduced the empty shell rate of walnut.Comprehensive evaluation showed that S1 spraying 200 times liquid microbial agents significantly affected walnut fruit kernel rate,yield and empty shell rate and walnut shoot growth.Therefore,it was preliminarily judged that200 times liquid microbial agents had the best treatment effect.