Abstract: Objective To investigate the expression of B7-H1 protein in gallbladder carcinoma tissues and to explore its role in the carcinogenesis and progression of gallbladder carcinoma. Methods The expression of B7-H1 protein in 60 cases of gallbladder carcinoma tissues were detected by immunohistochemistry(SP) method; 20 cases of corresponding non-tumor tissues and 20 cases of gallbladder adenoma polyp were served as control groups. Results The expression of B7-H1 protein in gallbladder carcinoma group was significantly higher than that in corresponding non-tumor tissues group(P=0.003) and gallbladder adenoma polyp group(P=0.035); the B7-H1 protein expression levels in Nevin(Ⅳ+Ⅴ) stage, TNM(Ⅲ+Ⅳ) stage and lymph node metastasis group were significantly higher than those in Nevin(Ⅰ+Ⅱ+Ⅲ) stage (P=0.041), TNM(Ⅰ+ Ⅱ) stage(P=0.049) and lymph node metastasis-free group(P=0.000); but the expression of B7-H1 protein had no relationship with age, gender or tumor differentiation(P>0.05). The three-year survival time of the patients with positive expression of B7-H1 protein was significant lower than those with negative expression of B7-H1 protein(P=0.029). Conclusion The overexpression of B7-H1 protein results in poor prognosis, indicating that B7-H1 protein plays role in the development, invasion and metastasis of gallbladder carcinoma.