Abstract: Objective To investigate the effects of all trans-retinoic acid(ATRA)on the expression of MAPK signal transduction.Methods The effects of ATRA on the cell proliferation was measured by methyl thiazolyl tetrazolium(MTT),and the expression of ERK1/2,P38,JNK and their phosphorylated proteins were measured by Western blot.Results The inhibitory rate was 10.2%±0.5%,15.3%±0.5%,17.0%±0.7%,28.4%±1.0% and 36.9%±0.7%,respectively,as SGC-7901 cells were exposed to 10^-9mol/L-10^-5mol/L ATRA for 48 hours.ATRA did not influence the expression of ERK1/2,P38,JNK and p-JNK,but significantly decreased p-ERK1/2,significantly increased p-P38.Conclustion It is suggested that ATRA could inhibit proliferation of SGC-7901 cells via regulating the ERK1/2 and P38 MAPK pathway.