Objective. We investigated whether miR-183 played a role in regulating mTOR expression and influencing autophagy of GC cells. Methods. Tumor tissues and paracancerous tissues were collected from GC patients to detect the expressions of miR-183, mTOR, autophagy-related proteins Beclin-1. SGC7901 cells were cultured in vitro and divided into 5 groups: MiR-NC group, MiR-183 mimic group, siNC group, small interfering RNA transfected (si)-mTOR group, miR-183 mimic + si-mTOR group, to compare the expression of mTOR, apoptosis rate and clonality in all groups, and detect the expressions of Beclin-1 under starvation condition. Results. The expressions of miR-183, Beclin-1 in GC tissues were significantly decreased, and the expression of mTOR was significantly increased compared with those in paracancerous tissues. There was a targeted-regulating relationship between miR-183 and mTOR. Compared with GES-1 cells, miR-183 expression was decreased and mTOR expression was increased in SGC-7901 cells, and under starvation condition, the expressions of Beclin-1 were decreased. After transfected with miR-183 mimic and/or si-mTOR, the expression of mTOR in SGC-7901 cells was decreased significantly, the cell clonality was significantly reduced, apoptosis was increased significantly, and cell autophagy activity induced by starvation was significantly enhanced. Conclusion. miR-183 can influence the proliferation, apoptosis and autophagy of GC cells through targeted inhibition of mTOR expression.