Objective To investigate the effects of hypoxic conditions on expressions of hypoxia-inducible factor 1α (HIF-1α) and P-glycoprotein (P-gp),and the relationship between HIF-1α and P-gp.Methods Tumor tissues from 54 cases of patients with colonic neoplasm in Xingtai People's Hospital were selected after operation from June 2013 to June 2015.The expressions of HIF-1α and P-gp in colonic tumor tissues were detected by using immunohistochemistry,and their correlations to clinical and pathologic features were analysed.The expressions of HIF-1α and P-gp in colonic tumor cell lines under normoxia and hypoxia conditions were detected by using cell smear method,and correlation between HIF-1α expression and P-gp expression was analysed.Results Among tumor tissues from 58 cases of patients with colonic neoplasm,the positive rate of HIF-1α expression was 58.62％,and that of P-gp expression was 46.55％.The positive rates of HIF-1α and P-gp expressions of patients on the Dukes stage C+D were significantly higher than those of patients on A+B phase (P＜0.05).Additionally,the positive rates of HIF-1α and P-gp expressions of patients with lymphatic metastasis were significantly higher than those of patients without lymphatic metastasis (P＜0.05).The HIF-1α expression was positively correlated with the P-gp expression (r=0.574,P＜0.01).For the same cell lines,the expression levels of HIF-1α and P-gp under hypoxia condition were significantly higher than those under normoxia condition,there were statistically significant differences (P＜0.01).While,under the same oxygen conditions,no statistically significant difference was found in expression levels of HIF-1 and P-gp among different colonic tumor cell lines (P＞0.05).Conclusion Overexpression and coexpression of HIF-1α and P-gp exist in colon cancer.The expression levels of HIF-1α and P-gp in patients with different Dukes stages and patients with or without lymph node metastasis are significantly different,and positive correlation is observed between the expression of HIF-1α and P-gp.Hypoxia condition can induce an increase in expressions of HIF-1α and P-gp in colonic tumor cells.