The objective of this study was to assess the meat quality in second filial hybrid offspring of MSTN −/− cloning boars × Chinese Bama sows with initial mean body weight of 90.52 ± 0.68 kg. Compared with wild-type pigs, the feed utilization rate of MSTN −/− pigs showed an increasing trend (adjusted P = 0.06), loin eye area of MSTN −/− and MSTN +/− pigs increased (adjusted P < 0.01) and thickness of subcutaneous fat decreased (adjusted P < 0.01), the proportion of polyunsaturated fatty acids in meat of MSTN −/− pigs increased (adjusted P < 0.05). By means of histochemical staining, immunofluorescence, scanning electron microscopy, qRT-PCR and WB technologies, it was verified that the decreased meat color score of MSTN −/− pigs was related to the increase of type IIB muscle fiber, and the increased pork tenderness was related to the decrease of collagen content. Overall, this research provides reference for the further utilization of MSTN gene mutant pigs. • Meat color score of MSTN −/− pig (F2) is lower, due to the increase of the proportion of type IIB muscle fibers. • Longissimus thoracis muscle of MSTN −/− pig (F2) has lower fat content and higher proportion of polyunsaturated fatty acid. • Meat of MSTN −/− pig (F2) is more tender, because of the decrease of collagen content. [ABSTRACT FROM AUTHOR]