The aim of this research was to determine the effects of plant growth-promoting rhizobacteria(PGPR) fertilizer on the biological characteristics,root activity,growth and construction of Cerasus pseudocerasus(Lindl.) G.Don(sweet cherry).To prepare sweet cherry biological-fertilizer(YMF),dominant bacteria YT-3,a type of PGPR,was extracted from rhizosphere soil of C.pseudocerasus trees by keeping green method and radish cotyledon weight increase method.Sweet cherry biological-fertilizer was prepared by compounding YT-3 and decomposed chicken manure(DCM).The effects of YMF,normal biological fertilizer(NMF) and DCM on biological characteristics of C.pseudocerasus rhizosphere soil were studied in Yiyuan sweet cherry orchards.And the effects of YMF,DCM and NMF on the root activity,growth and construction of C.pseudocerasus were also investigated.The results showed that YMF increased the amount of bacteria and total microorganism amount in rhizosphere soil of C.pseudocerasus,but the fungus amount was decreased significantly.However,YMF had no influence on actinomycetes amount in rhizosphere soil.Root activity in YMF was significantly increased by 15.33%,22.49% and 13.25% than that in CK,NMF and DCM,respectively.YMF had great influence on the root growth and construction of C.pseudocerasus.Root weight,especially fine root weight in 0～40 soil profile of YMF was significantly increased.Rhizosphere soil pH value in YMF decreased by 8.61% than that in NMF.In addition,YMF significantly enhanced available phosphorus and potassium contents by 17.21% and 9.56%,respectively,compared to that in NMF.However,it had no effects on available nitrogen content in sweet cherry rhizosphere soil.Moreover,PGPR fertilizer increased the cation exchange capacity of rhizosphere soil,which benefited the nutrient retain and uptake of C.pseudocerasus.As a result,plant growth-promoting rhizobactera biological-fertilizer benefited the ecological environment of sweet cherry rhizosphere soil,improved nutrient availability and cation exchange capacity,increased the root activity and benefited the root growth,especially fine root growth in top soil(mainly 0～40 cm).