Branches returning is not only an effective way of waste resource utilization，but also an important approach to improve soil comprehensive fertility.In the present study，a branches mulching experiment was conducted from 2017 to 2018 and the pear tree cultivar was ‘Jinmi’ pear.Four treatments were set up:no branches mulching at 0 kg/plant(R0)，low branches mulching rate at 4 kg/plant(R4)，conventional branches mulching rate at 8 kg/plant(R8) and high branches mulching rate at 12 kg/plant(R12).In order to study the effect of different branches mulching rate on soil physico-chemical properties and microbial community structures，the general analysis method and Illumina MiSeq high-throughput sequencing technology were adopted，after 8 months of the return of pear branches to the filed.The results showed:With the increasing branches mulching rate，R4 treatment improved soil clay content，R8 and R12 treatment improved soil sand content.The highest microbial biomass carbon and nitrogen were both obtained in R4 treatment，which were 123.82 and 34.04 mg/kg，respectively.Compared with R0，branches mulching (R4～R12) had no significant effect on bacterial diversity，but increased the relative abundance of Proteobacteria，and decreased Chloroflexi.Branches mulching altered the bacterial community structures at order level.For the fungi，R4 treatment had the highest chao1 index.At fungal phylum level，branches mulching (R4～R12) increased the relative abundance of Basidiomycota，but decreased the relative abundance of Ascomycota.At fungal order level，branches mulching increased the relative abundance of the relative abundance Agaricales and Sordariales，but decreased Microascales.The redundancy analysis showed that soil fulvic acid and mechanical composition(clay and silt)were the main environmental driving factors.Therefore，under the current condition of pear branches mulching，considering the changes in soil physico-chemical properties and microbial community structures，the optimal branches mulching rate in the short-term was 4 kg/plant.