[Objectives] In this study, we took Yak (Bos mutus) as studying object to illustrate the impact of low oxygen environment on the expression level of the three subunit genes (lactate dehydrogenase A, LDHA; lactate dehydrogenase B, LDHB; lactate dehydrogenase C, LDHC) of lactate dehydrogenase (LDH) gene in skeletal muscle. [Methods] Adult male Yaks that inhabit in different altitudes, including high altitude (altitude 4 200 m), medium altitude (altitude 3 200 m) and low altitude (altitude 1 900 m) were used in our study. Real-time PCR and western blot were utilized to detect the mRNA and protein content of various skeletal muscle subtypes in Yaks at different altitudes. The experimental data were compared by one-way analysis of variance (ANOVA) using SPSS 23.0. [Results] The results showed that LDHA mRNA expression decreased in the Yak skeletal muscle with elevation increase (Fig. 2). LDHB mRNA expression was first reduced and then increased in the Yak skeletal muscle with increasing elevation, and the expression of LDHB mRNA was highest among high-altitude Yaks (2.82 ± 0.12), and the expression of LDHB mRNA at high altitude was significantly different from that of low-altitude (1.01 ± 0.07) (P < 0.05) and medium-altitude Yaks (0.73 ± 0.06) (P < 0.05) (Fig. 2). The expression of LDHC mRNA decreased with elevation, and the difference between low altitude (1.10 ± 0.16), medium altitude (0.86 ± 0.16) and high altitude (0.69 ± 0.12) was significant (P < 0.05) (Fig. 2). The expression of LDHA and LDHC proteins decreased with the increasing altitude, the expression of LDHA protein was significantly different between low altitude (1.00 ± 0.00), medium altitude (0.88 ± 0.02), and high altitude (0.75 ± 0.02) (P < 0.05) (Fig. 3a, b), the expression of LDHC protein was significantly different between low altitude (1.00 ± 0.00), middle altitude (0.89 ± 0.02), and high altitude (0.74 ± 0.02) (P < 0.05) (Fig. 3e, f); with an elevation in altitude, the expression of LDHB protein firstly reduced and subsequently returned to normal, and high-altitude Yaks (1.37 ± 0.02) had significantly higher levels of LDHB protein expression in their skeletal muscles than did low-altitude (1.00 ± 0.00) (P < 0.05) and medium-altitude Yaks (0.95 ± 0.01) (P < 0.05) (Fig. 3c, d). [Conclusion] Lactate dehydrogenase is the key enzyme catalyzing conversion of pyruvate and lactate, its content and activity are regulated by genes. The results of this experiment report different mRNA expression and protein content of LDH in Yak skeletal muscle at different altitudes, which indicate adaptation of skeletal muscle in plateau-living Yaks to different oxygen partial pressure environments, as well as corresponding changes in pyruvate and lactic acid metabolism in skeletal muscle, and the oxidative metabolism capacity of anaerobic oxidation.