Abstract: The aim of this study was to clone the prospero-related homeobox protein 1（PROX1） gene of the Nubian goat（Capra nubiana）, and to detect the mRNA expression of genes related to myoblast differentiation and the transformation of myofiber types after overexpressing PROX1 gene in myoblasts of Nubian goat. This study aimed to provide reference for studying the regulatory role of the PROX1 gene in ske-letal muscle development. The cDNA of the longest dorsal muscle tissue of the Nubian goat was used as the template to clone the PROX1 gene, and a eukaryotic expression vector pEGFP-N1-PROX1 was successfully constructed and identified. These constructs were then transfected into Nubian goat myoblasts. The differentiation medium was changed 24 hours later, and the cells were collected after differentiation for 6 days. The expression of marker genes for cellular differentiation, genes related to the NOTCH signaling pathway, and genes related to the types of myofibers in skeletal muscles were examined by RT-qPCR in the cells. The results of the study showed that the coding sequence（CDS） length of the PROX1 gene was 2 214 bp in the Nubian goat, encoding a polypeptide with 737 amino acids. The results of the RT-qPCR showed that the PROX1 gene promoted myoblast differentiation by inhibiting the NOTCH signaling pathway and up-regulating the expression level of cell differentiation marker genes（P＜0.05）. The PROX1 gene also mediated the CaN/NFAT signaling pathway and significantly down-regulated the mRNA expression level of MYH2 and MYH4 genes（P＜0.05）. This study preliminarily determines that the PROX1 gene regulates myoblast differentiation and the transformation of muscle fiber types. The research results provide theoretical data for further enriching the understanding of the molecular mechanisms of muscle growth and development.