Abstract: The research aimed to seek the mutation sites of HSP70 gene and find the quantitative trait locus which provided a basis for molecular marker-assisted selection. Sixty Jinyun ducks were used as the experimental animals. Partial fragments of duck HSP70 gene were amplified by PCR method. The polymorphisms of the target fragment were detected by the methods of sequencing， and then the least square mean and genetic variance of different genotypes at polymorphic loci were analyzed. The results showed that there were two SNPs （1476（C/T） and 1596（C/T）） in HSP70 gene. The frequencies of CT， TT and CC were 70.00%， 16.67% and 1333% at the C1476T site， but 48.33%， 41.67% and 10.00% at C1596T site， respectively. Association analysis showed that the egg production of genotype CC was significantly higher than genotype CT and genotype TT for laying performance in 1476（C/T） locus （P<0.05）. The 1596（C/T） site showed no significant correlation with laying performance （P>0.05）. The results provided a preliminary theoretical data for molecular assisted breeding of laying duck， but because of the sample was small， it is necessary to increase the sample size for further research and analysis．

Key words: domestic duck, single nucleotide polymorphisms （SNP）, HSP70, laying performance