To understand the expression difference of IGFBP-1 between diploid and tetraploid Misgurnus anguillicaudatus,and their relationship with DNA methythylation,we cloned the CDS and promoter sequence of the IGFBP-1 gene,and analyszed the expression level and DNA methylatyion rate in diploids and tetraploids using qRT-PCR method and bisulfite sequencing technology (BSP),respectively. The results showed that,the CDS of IGFBP-1 was 789 bp,encoding 262 amino acid,and 5 basepair difference but no amino acid difference were found between diploids and tetraploids. We cloned 2 341 bp and 2 331 bp promoter sequences in diploids and tetraploids,respectively,with the sequence similarity of 99%. The core transcription element TATAbox,and transcription factor binding sites such as SP1,CREB,C/EBP,POU2F2,GATA2/3/4 and SRY were observed in the promoter. The IGFBP-1 gene was mainly expressed in the liver,and the expression level was significantly higher in tetraploids than in diploids (P＜0.01). The methylation level of promoter and 1st exon were lower in teterploids than in diploids,expecially in the liver (P＜0.01). In conclusion,in the liver,the major expression tissue of the IGFBP-1 gene,the mRNA expression level and DNA methylation level were negatively correlated,suggesting that the higher DNA methylation rate in promoter may suppressed the expression of IGFBP-1 in the diploid M. anguillicaudatus.