Abstract: Myosin heavy chain (MYH) participates in hypertrophy and hyperplasia of muscle fibres in fish and plays an important role in muscle growth and contraction. In order to screen single nucleotide polymorphism (SNP) sites associated with growth traits, we applied the PCR amplification method to obtain the nucleotide sequence of MYH in the cultured marine fish, the hybrid grouper (Epinephelus fuscoguttatus ♀ × E. polyphekadion ♂), and then used the correlation analysis to detect the SNPs related to its growth traits. The results show that the sequence length of the MYH was 12 129 bp, including 36 exons and 35 introns, encoding 1 934 amino acids. Four typical domains in MYH were detected, namely Myosin_N, MYSc, IQ and Myosin_tail_1. Comparative analysis reveals that high conservation in nucleotide sequence and protein domain of MYH was manifested in Perciformes, Tetraodontiformes and Pleuronectiformes species. Sixty-two SNP loci were found in the MYH. Eight SNP loci were in Hardy-Weinberg equilibrium state. Twelve SNP loci were located on exons, significantly correlated with growth traits, such as body mass and total length. Among the 12 SNP sites, only g5417 C>G was a missense mutation, resulting in the transformation from alanine to glycine. Other loci were synonymous mutations. These SNP sites related to growth provide candidate sites for screening the growth-related molecular markers in the hybrid grouper.