Objective To evaluate the relationship among bladder cancer cell proliferation and invasion,microRNA-143 and 29a,and ras association domain family 1A (RASSF1A) methylation.Methods MiR-143 and miR-29a mimics were transfected to T24 cell lines.Transfection efficiency was confirmed by reverse transcription polymerase chain reaction (RT-PCR).All cell lines were divided into four groups:WT group (wild T24 cell lines without any treatment),NC group (transfected by negative control mimics),M1 group (transfected by miR-143 mimics) and M2 group (transfected by miR-29a mimics).Apoptosis rates,cell cycle,cell invasive inhibitor rates,RASSF1 A gene expression and methylation were detected.Results Transfection was successful confirmed by RT-PCR.Apoptosis rates of WT,NC,M1 and M2 group were 2.5％,3.4％,12.4％ and 13.3％ respectively.S-phase cells in M1 and M2 group increased significantly.Cell invasive inhibitor rates of NC,M1 and M2 group were 2.0％,16.5％ and 13.2％ respectively which showed the rates in M1 and M2 group were higher than NC group (P ＜0.05).RASSF1A gene expression was upgraded in M2 group and no changes were found in M1 group.What's more,MSP results showed that RASSF1 A gene was partial methylated in M2 group while it was completely methylated in other groups.Conclusion T24 bladder cancer cell proliferation and invasion decreased after miR-143 and miR-29a transfected.miR-29a transfection may inhibit RASSF1 A gene methylation and lead to gene expression uploaded.