The histology of early gonad differentiation was observed,and expression of the genes related to gonadal development (hormad1,dmrt1a) at different early development stages (4，14，21，23，50，60 and 65 dph (days posthatch)) and in different tissues (gonad,liver,muscle,intestine,gill,fin,skin and brain) of the hybrid triploid loach (4 n ♀×2 n ♂) was quantitatively detected by fluorescence quantitative PCR (qRTPCR). The results showed that at different early developmental stages,thehormad1 and dmrt1a genes were expressed the highest on 4 dph,followed by 14 dph and the lowest on 50 dph. In different tissue,the hormad1 gene was expressed highest in the female fins and lowest in the liver,highest in the male gonads and lowest in the liver. The expression of the dmrt1a gene was highest in the gonads of both male and female loaches and lowest in the brain. The differentiation and occurrence of gonads at early stage of the hybrid triploid loach was not different from that of the diploid loach. The primitive germ cells and its migration,formation of the primitive gonads and differentiation of the gonads were observed. In summary,thehormad1 and dmrt1a genes play a certain role during early gonadal development.