Objective To evaluate the expression of γ-synuclein protein （SNCG） in carcinoma of bile duct andnormal bile duct tissues， and its clinical significance. Methods The expressions of SNCG were detected by SP immuno-histochemical in 60 cases of cholangiocarcinoma and 34 cases of normal bile duct tissues， and to analysis its relationship with the clinical pathological characteristics of cholangiocarcinoma. Results The positive expression rate of SNCG in carcinoma of bile duct tissues was 73.33% （44/60）， which was higher than that in normal bile duct tissues （P＜0.01）. The positive expression of SNCG in carcinoma of bile duct tissues was correlated with the depth of tumor invasion and lymph node metastasis （P＜0.01）， but not related to patients’ age， gender， and the degree of tumor differentiation （P＞0.05）. Conclusions The expression of SNCG is correlated with the cholangiocarcinoma occurrence， development， invasion， and metastasis. SNCG plays an important role in the infiltration and metastasis of carcinoma of bile duct. SNCG is expected to become a new cancer tumor marker， which can provide a basis to prognosize and to formulate the corres-ponding therapy plan.