Objective To study the inhibitory effect of miR-199a on bladder cancer.Methods T24 bladder cancer cells were divided into control group, pre-scamble group and pre-miR-199a group according to different treatment.Cell proliferation was assayed by MTT, cell apoptosis and cell cycle by flow cytometry, and cell invasion by Transwell.ResuIts The OD value of pre-miR-199a group (0.436 ±0.042) was significantly lower than that of control group (0.634 ±0.020) and pre-scamble group (0.601 ±0.059)(P<0.05).Cell apoptosis of pre-miR-199a group(19.25 ±1.57)% was higher than that of control group(10.19 ±0.98)% and pre-scamble group(12.27 ±1.38)%(P<0.05).The cell ratio in G1 phase of control group、pre-scamble group and pre-miR-199a group was 45.09%, 47.57%, and 58.62%, respectively.The cell cycle arrested in G1 phase after transfected with pre-miR-199a.The cells migration number of pre-miR-199a group (46.00 ±1.58) was lower than those of control group(67.00 ±1.58) and pre-scamble group(61.20 ±1.30)(P<0.05).ConcIusion MiR-199a could inhibit the growth of bladder cancer cells.