Objective To investigate the expressions of heat shock protein 27 (HSP27), Bcl-2, and Bax proteins of the nerve cells after spinal cord ischemia/reperfusion injury (SCII) in rats and their relationship. Methods Seventy adult male Sprague Dawley rats (weighing, 200-220 g) were randomly divided into the sham operated group (sham group, n=35) and the SCII group (n=35). Only the left renal artery was exposed with no occlusion of the abdominal aorta in the rats of sham group. The left renal artery was exposed with occlusion of the abdominal aorta for 20 minutes in the rats of SCII group. At 4, 8, and 12 hours and at 1, 2, 3, and 5 days, reperfusion treatment was performed in 5 rats respectively, and then the spinal cord tissue was harvested to detect the expressions of HSP27, Bcl-2, and Bax protein of the nerve cells by using immunohistochemistry staining. Results The HSP27 began to express at 4 hours, reached the peak at 3 days, and decreased at 5 days in SCII group; significant differences were found between at 3 and 5 days and at the other time points (P lt; 0.05). The Bcl-2 expression increased at 4 hours, reached the peak at 1 day and maintained a high level at 2 days, and then gradually decreased; significant differences were found between at 1 and 2 days and at the other time points (P lt; 0.05). The Bax expression reached the peak at 12 hours and 3 days, and decreased at 5 days; significant differences were found between at 12 hours and 3 days and at the other time points (P lt; 0.05). A little expression of each protein was observed in sham group at different time points; the expressions of HSP27, Bcl-2, and Bax proteins in SCII group were significantly higher than those in sham group at different time points (P lt; 0.05). Conclusion There may be the time window of self repair after SCII. High expression of HSP27 has an obvious protective effect on the SCII in rat, by promoting the expression of the anti-apoptotic protein Bcl-2 and reducing the expression of the pro-apoptotic protein Bax so as to inhibit spinal cord cell apoptosis.