Abstract: In order to explore the molecular regulation mechanism of growth traits of Larimichthys crocea, in this experiment, 182 individuals with fast growth rate average body weight (527.1 ± 83.6) g and 230 individuals with slow growth rate average body weight (238.4 ± 52.3) g were selected from L. crocea cultured in the same cage, a total of 412 individuals were studied. The muscle tissues were subject to total RNA extraction and sequenced by transcriptome, and the differential expression of genes between the two groups was analyzed. According to Padj < 0.05 and abslog₂(FoldChange) > 1, 227 differentially expressed genes were screened, including 125 up-regulated genes and 102 down-regulated genes. The annotation rates of differentially expressed genes in NCBI-nr and Uniprot (Swiss-Prot) databases were 99.12 % and 81.94 %, respectively. Based on the functional annotation results of differentially expressed genes, candidate functional genes that may be related to muscle growth, such as gdf9, ckm, tnni2 and des, were screened. GO and KEGG analysis predicted some information related to muscle growth, such as actin filament organization, actin cytoskeleton organization, actin filament-based process, microtubule organizing center and developmental growth in GO term, and cytokines and growth factors, fatty acid biosynthesis, transforming growth factor-beta signaling pathway (TGF-β signaling pathway), insulin signaling pathway and regulation of actin cytoskeleton in KEGG pathway. WGCNA analysis showed that there was a strong correlation between purple module and body weight traits, and its core genes myoz1, tpm1 and tnni2 may be related to muscle growth. These results provide a reference for further verification of the functions of related genes and the analysis of the molecular regulation mechanism of growth traits of L.crocea.