To reveal the characteristics of the mrf4 gene in the mandarin fish and analyze the expression pattern of mrf4 in different tissues of the adult mandarin fish and in embryos from different developing stages. Reverse transcriptional PCR was used to amplify the mrf4 cDNA sequence of mandarin fish, which was inserted into a cloning vector and sequenced. Quantitative real-time PCR was conducted on samples from different tissues of adult mandarin fish and from embryos of different stages. The results show that the mrf4 gene of mandarin fish is 726 bp in length and encodes 241 amino acids which form a basic helix-loop-helix (bHLH). Expression of mrf4 gene was observed in all tested samples including white muscle, red muscle, heart and brain of adult mandarin fish and embryos of different stages. Among the tissue from adult mandarin fish, mrf4 gene expression in red muscle was significantly higher than that in the other tissues (P<0.05). For embryos, the expression of the mrf4 increased from the gastrular stage to muscular effect stage, and decreased from the cardiac stage to larval fish with expression in muscular effect stage the highest, which is significantly higher than samples from other stages (P<0.05).