Renal cell carcinoma (RCC) is a heterogeneous histological disease and the most common kidney cancer. The mortality rate of RCC remains high despite the improved treatment. Sinomenine is an isoquinoline extracted from Chinese medicinal plant Sinomenium acutum, famous for its ability to suppress several cancer cell types. Our research aimed to explore the anti-cancer potential of sinomenine in RCC. Results showed that sinomenine reduced the viability by reducing sphere-forming ability and enhancing pro-apoptosis effect in ACHN cells in a dose dependent manner. The expression levels of proliferation/apoptosis markers further validated the result. In addition, sinomenine significantly regulated the level of autophagy-related proteins with decreased expression of p62, and increased Beclin1 and LC3 II/LC3 I. Furthermore, phosphatidylinositol-3 kinase (PI3K)/AKT/mechanistic target of rapamycin (mTOR), the negatively regulated cell autophagy signaling pathway, was inhibited by sinomenine with decreased membrane translocation of AKT in ACHN cell lines. All in all, our study demonstrated that sinomenine promoted apoptosis in RCC via enhancing autophagy through PI3K/AKT/mTOR pathway.