Purpose: To detect the expression of AGO1 in cholangiocarcinoma and explore its role and significance in the progression of cholangiocarcinoma. Patients and methods: Using immunohistochemistry, Western blotting and qPCR, we examined the expression of AGO1 in cholangiocarcinoma tissues. Through the analysis of clinical case data, the relationship between AGO1 and clinical prognosis was explored. The effect of AGO1 on cholangiocarcinoma was verified by cell functional experiments. Finally, we examined the effects of AGO1 on EMT-related proteins and signaling pathways. Results: AGO1 is significantly upregulated in cholangiocarcinoma and is associated with the prognosis of cholangiocarcinoma. AGO1 can significantly increase the proliferation, migration and invasion of cholangiocarcinoma cell lines. AGO1 affects the prognosis of cholangiocarcinoma by affecting epithelial-mesenchymal transition (EMT)-related TGF-β-PI3K-AKT signaling pathways. Conclusion: AGO1 is an independent predictor of cholangiocarcinoma prognosis and a potential target for the treatment of cholangiocarcinoma.