In order to further investigate the sex determination and sex differentiation mechanism of large scale loach Paramisgurnus dabryanus ,two degenerate primers,SoxN and Sox9, were used to carry out PCR amplification of the genomic DNA and RT-PCR analysis of the gonad tissues.Thirteen genes of the Sox family including pdSox1 , pdSox2,pdSox3 , pdSox4,pdSox11 , pdSox14 , pdSox19 and pdSox21 were cloned from the genomic DNA of P.dabryanus with the SoxN primer and classified as the SoxB and SoxC groups.Another five Sox genes including pdSox8 and pdSox9, with one intron starting at the same position,were obtained by using the Sox9 primer and classified as the SoxE group.Based on the genetic distance of the HMG-box amino acid,all the eighteen pdSox were orthologous to the Sox genes of mouse or zebrafish on the NJ phylogenetic tree.Six of the 13 Sox genes including pdSox4, pdSox8 , pdSox9 , pdSox11 , pdSox14 and pdSox19 had two or more copies.Moreover,the results of RT-PCR and sequence analyses with the Sox9 primer showed that pdSox9a was expressed in the testis whereas pdsox8a was expressed in the ovary.The present results suggested that pdSox8 and pdSox9 were sex-related genes and they might play a role in the sex differentiation of P.dabryanus .