Objective To genotype Oncomelania hupensis， based on microsatellites， in different snail-bearing environments in Jiaxing City， Zhejiang Province， for population genetics analysis in order to explore the reasons and influencing factors for the existence or proliferation of snails and to provide scientific basis for effective monitoring and control of snails.

Methods A total of 90 snail samples from three populations were collected in Yaobang Village （YB） and Sanxing Village （SX） in Pinghu City， and Yunhe Farm （YH） in Xiuzhou District， all were selected for snail checking in key snail habitats of Jiaxing City in 2022. DNA of the snails was genotyped and analyzed for population genetics using nine microsatellite loci.

Results A total of 84 alleles were observed， and the mean number of alleles （Na） was 7.889， 5.667， and 3.778 for YB， SX， and YH respectively； the number of effective alleles （NeA） was 4.807， 3.329， and 2.294， respectively； and the coefficients of inbreeding （F_IS ） were 0.400， 0.377， and 0.493， respectively. Under the Infinite Allele Model （IAM）， the SX and YH might have a recent bottleneck. The NEstimator and LDNe software calculated effective population sizes （Ne） were above 31.9. AMOVA analysis showed that the variation of snails in the three populations mainly existed among individuals， accounting for 41.4% of the total variation. The value of the index of genetic differentiation between populations （F_ST ） was 0.286， indicating a high degree of genetic differentiation. The results of the principal component analysis and phylogenetic tree were consistent， and the three populations were divided into two lineages， YB and SX were one lineage， and YH belonged to another independent lineage. Population history and dynamics analysis showed that the gene flow of the three populations was insufficient， population divergence history indicated that YH might have diverged from SX first， and YB was produced by the contact fusion of SX and YH.

Conclusion The genetic diversity of snail populations in Jiaxing City is generally low， and the snail populations are unstable， with a great degree of genetic differentiation and insufficient gene flow among populations. This study can provide a basis for evaluating the effectiveness of the control of the snail as well as monitoring the trend of the spread of the snail.