Objective:To explore the effects of microRNA143,microRNA145 transfection on biological behaviors of cholangiocarcinoma cell line QBC939,and the relationship between microRNA143,microRNA145 and extrahepatic cholangiocarcinoma. Methods:RNA of 11 pairs of specimens of extrahepatic cholangiocarcinoma and normal bile duct was extracted,and then the expression of microRNA143 and microRNA145 was detected by real-time PCR. Expression plasmid of microRNA143(or microRNA145) was transiently transfected into human cholangiocarcinoma cell line QBC939,and then cell proliferation,cell cycle and cell apoptosis were determined by MTT and flow cytometry assay. Results:Compared with normal bile duct,the relative expression ratio of microRNA143 and microRNA145 in extrahepatic cholangiocarcinoma respectively was 0.048,0.035(P < 0.05). Compared to control group,cholangiocarcinoma cell growth was effectively inhibited in microRNA143 group and microRNA145 group,the percentage of cells in G1 phase was increased[(microRNA143 group and microRNA145 group:66.08%±1.93% and 65.57%±1.85%)vs(control 42.87%±1.37%)],the percentage of cells in S phase was decreased[(19.16%±1.15% and 21.40%±1.65%) vs(control 38.76%±1.83%)]and the ratio of cell apoptosis was increased[(18.49%±2.26% and 16.89%±2.47%)vs 4.68%±1.65%](P < 0.05). Conclusion:The expression of microRNA143 and microRNA145 is down-regulated in extrahepatic cholangiocarcinoma,and they may correlate with tumorigenesis. With up-regulation of microRNA143 or microRNA145 expression in cholangiocarcinoma cell line QBC939,cell proliferation can be inhibited,cell cycle can be arrested and cell apoptosis can be increased.