Through PCR amplification,the β-actin gene promoter fragment SZ21(2 398 bp ) of Leuciscus merzbacheri was obtained.We forecasted its transcriptional regulation elements using bioinformatics method.In view of its ORF and introns sequence,the system development was analyzed between L.merzbacheri and other closely related fish species.Three core promoter transcriptional elements were situated in the transcriptional start site(+1) upper -89,-59,-26,including the CAAT-box,CArG motif,TATA-box.Results of putative transcription binding sites analysis of the promoters revealed the presence of several critical transcription binding sites such as the MEF2,SATB,CHRF,INRE,MTEN,E-box,RU49,ZBPF,CREB,Enhance region and CEBP in the further promoter.The splice sites abided by GT…AG rule in the spliceosome introns.The promoter SZ21 sequence included the intron 1,intron 2,intron 3,and 155 amino acids.The system development analysis of three introns showed that Megalobrama amblycephala had more close relationship to Ctenopharyngodon idella and Mylopharyngodon piceus than L.merzbacheri. This is not consistent with the traditional classification,and the reason needs further investigation.