[Objectives] This study aims to clarify the expression characteristics of genes regulating fast and slow skeletal muscles of Yak Bos mutus at different altitudes and their adaptive mechanisms to hypoxia. [Methods] The Yaks were selected from Hualong County (1 900 m above sea level, hereinafter referred to as the low altitude group), Haiyan County (3 200 m above sea level, hereinafter referred to as the middle-altitude group) and Banma County (4 200 m above sea level, hereinafter referred to as the high-altitude group), Qinghai, China, with the low-altitude Yak and Cattle B. taurus were taken as the control. Real-time quantitative PCR and Western blotting technology were used to detect changes in mRNA expression and protein content of genes regulating fast and slow skeletal muscle in Yak at different altitudes, respectively. [Results] The results showed that with the increase of altitude, the expression of MyoG that regulates the expression of fast muscle, gradually increased, the mRNA of MyoD which regulates the expression of slow muscle first decreased and then increased, while the protein expression of slow muscle first increased and then decreased (Fig. 2, 3). In addition, the expression of PGC-1 mRNA and PGC-1 protein gradually increased with altitude (P < 0.05) (Fig. 4, 5). [Conclusion] The above results showed that the mRNA expression of MyoG, MyoD and PGC-1 may be associated with the hypoxic environment. The muscle fibre types and the expression of regulatory genes of skeletal muscles changed to adapt to the low oxygen environment. The present study provides basic data for the in-depth study of the mechanism of hypoxia adaptation in Yaks at different altitudes in Qinghai Province.