In order to investigate the relationship between the tendon development related genes (tnmd/xirp2a) and the intermuscular bone in blunt snout bream (Megalobrama amblycephala),we firstly obtained the cDNA sequence of tnmd/xirp2a by cloning. The fulllength cDNA of tnmd is 1 420 bp,including an open reading frame (ORF) of 906 bp encoding 301 amino acids. The cDNA sequences of xirp2a is 11 715 bp in length,including an ORF of 9 522 bp encoding 3 174 amino acids. Phylogenetic analysis showed that the tnmd gene was lowly conserved among different vertebrates. The tnmd protein had a sequence deletion compared to mammals and poultry. The tnmd/xirp2a expression in the muscle and intermuscular bone was significantly higher than that in other tissues (P<0.05). The tnmd expression in the muscle was significantly higher than that in the intermuscular bone (P<0.05),while the result of xirp2a was the exact opposite. During intermuscular bone development,the tnmd mRNA was significantly higher at stage Ⅲ than that at the other three stages. However,there was no significant differences of the xirp2a expression among stages Ⅱ,Ⅲ and Ⅳ (P＞0.05). Our results indicate that the tnmd gene may play possible regulation roles during the intermuscular bone development,while the relationship between the xirp2a gene and the intermuscular bone development needs to be further studied. The results of this study provide theoretical support for the derivation of intermuscular bone from the tendon.