〔Abstract〕 Objective To investigate the effect of miR-143 on the proliferation and apoptosis of prostate cancer cell line PC3. Methods The experiment was divided into non transfected PC3 cells group(PC3 group), transfected with miR-NC group(PC3/miR-NC group) and PC3 cells stably expressing miR-143 group(PC3/miR-143 group), and identified by immunofluorescence and real-time PCR. The effect of miR-143 on the proliferation of PC3 cells by CCK-8 method. The effect of miR-143 on PC3 cells apoptosis was analyzed by flow cytometry. The online analysis software was used to predict the target genes of miR-143, and then the luciferase reporter gene detection plasmid was constructed. The targeted binding sites of miR-143 and target genes were analyzed by luciferase assay. Results The expression level of miR-143 in PC3/miR-143 group was significantly higher than that of PC3 group(P<0.01) and PC3/miR-NC group(P<0.01). CCK-8 test showed that the cell proliferation ability of PC3/miR-143 group decreased significantly compared with PC3 group(P<0.05) and PC3/miR-NC group(P<0.01). The results of flow cytometry showed that the apoptosis level of PC3/miR-143 group was significantly higher than that of PC3 group and PC3/mir-nc group(P<0.01). Online analysis software predicted that miR-143 could target 3 ′-UTR binding to Trefoil Factor 3(TFF3); The results of dual luciferase reporter gene further confirmed that miR-143 could target the 3′-UTR of TFF3. Real time PCR results showed that overexpression of miR-143 could significantly inhibit the expression of TFF3 in PC3 cells. Transfection of TFF3 eukaryotic expression plasmid into PC3/miR-143 group could counteract the effect of miR-143. Conclusion MiR-143 inhibits the expression of TFF3 and the proliferation of PC3 cells by targeting the 3 ′-UTR of TFF3.