Objective To investigate the mRNA level of heat shock protein 47 (HSP47) in the myocardium from the rats under chronic hypoxic condition, and explore its correlation with serum contents of procollagen Ⅰ C-propeptide (PⅠCP) and procollagen Ⅲ N-propeptide (PⅢNP) and myocardial fibrosis. Methods Hypoxic environment was simulated to establish rat model of chronic hypoxia. A total of 40 SD rats were randomly divided into 5 groups (8 animals in each group), that is, normal control group, and the 4 groups under chronic hypoxic condition for 7,4, 21 and 28 d respectively. Real-time quantitative PCR (q-PCR) was used to detect the myocardial expression of HSP47 mRNA, and ELISA was adopted to measure the serum and myocardial contents of P[KG-*3]Ⅰ[KG-*4]CP and PⅢNP. HE and MASSON staining were used to observe the histopathological changes in the control group and chronic hypoxia groups. Results Compared with the control group, the mRNA level of HSP47 was increased in the model groups (P<0.01), so were the serum and myocardial contents of P[KG-*3]Ⅰ[KG-*4]CP and PⅢNP (P<0.01). The expression level was positively correlated with the serum contents of the 2 peptides (P<0.01). HE and MASSON staining indicated that extensive myocardial fibrosis was observed in the chronic hypoxic groups. Conclusion The expression of HSP47 mRNA is positively correlated with serum contents of P[KG-*3]Ⅰ[KG-*4]CP and PⅢNP under chronic hypoxic condition. Our findings suggest that HSP47, as a chaperone myocardial collagen, is involved in the myocardial fibrosis induced by chronic hypoxia.