Abstract: Objective To observe the effect of miR141 on the proliferation and cell cycle in LNCa P human prostate cancer cells. Methods The cancer tissues and adjacent tissues of patients with prostate cancer in our hospital from December, 2015 to June, 2017 were collected, and the miR141 expression were detected by using q PCR. The expression of miR141 in LNCa P cell was also detected. LNCa P cells were divided into LNCa P group (without transfection), mimics group (transfected with miR141-mimics) and inhibitor group (transfected with miRNA-141 inhibitor) to observe its transfection efficiency. The increment rate of the three groups was detected by MTT method, and the cell cycle was detected by flow cytometry. The expression of P27, CDK4 and Cyclin D1 were detected by WB. Results The levels of the miRNA-141 in cancer tissues were significantly higher than that of the adjacent tissues (P<0.05), and the levels of the miRNA-141 in the LNCa P cells were lower than those of the cancer tissues (P<0.05), but slightly higher than those of the adjacent tissues. After LNCa P cells transfected with miRNA-141-mimics, miRNA-141 expression was significantly increased (P<0.05). After the LNCa P cells were transfected, miRNA-141 expression of mimics group and inhibitor group were slightly higher than that of LNCa P group. When LNCa P transfected miRNA-141 mimics 48 h, the cell proliferation rate of mimics group was lower than LNCa P and inhibitor group. After LNCa P transfected miRNA-141 mimics, cell cycle was blocked in G₁ phase. Compared with LNCa P group and inhibitor group, the mimics group significantly increased P27, while CDK4 and Cyclin D1 decreased significantly. Conclusion MiR141 can affect LNCa P proliferation and block LNCa P in G₁ phase.