[Objectives] This study aims to clarify the expression patterns and distribution characteristics of heat shock protein 70 (HSP70), a key inducible protein in the heat shock response, in the skeletal muscle of Yaks (Bos grunniens) across three altitude gradients. [Methods] Skeletal muscle tissues of Yaks were collected fromthree altitude groups:Hualong Hui Autonomous County (1 900 m, low-altitude group), Haiyan County (3 200 m, mid-altitude group), and Banma County (4 200 m, high-altitude group) in Qinghai Province, China. Quantitative real-time PCR was employed to detect HSP70 mRNA expression in skeletal muscle, while Western blotting and immunohistochemistry were utilized to analyze the expression levels and spatial distribution characteristics of HSP70 protein across three altitude gradients. [Results] The mid-altitude group exhibited minimal HSP70 expression and a complete absence of nuclear immunoreactivity in myofibers. In contrast, both the low- and high-altitude groups showed significantly increased HSP70 expression in Yak skeletal muscle. Immunohistochemistry further revealed that HSP70 was present in both the cytoplasm and the nucleus of muscle fibers, with notable enrichment in the nuclear compartment (Fig. 1). The quantitative real-time PCR and Western blotting revealed that with increasing altitude, both HSP70 mRNA and protein showed a trend of first decreasing and then increasing, indicating an altitude-specific expression threshold (Figs. 4, 5). [Conclusion] These findings demonstrate that HSP70 expression in Yak skeletal muscle follows an altitude-dependent pattern. Furthermore, the observed pattern suggests a threshold effect that may optimize energy allocation. This study elucidates a potential molecular mechanism by which Yaks adapt to the plateau’s hypoxic environment, highlighting the critical role of HSP70 in this process. Additionally, our findings establish a framework for future research into the molecular regulatory network underlying adaptive evolution in plateau-native animals.