Abstract： Objective To investigate the proliferation inhibition and apoptosis induction effect of thalidomide(Thal) and its joint effect with 5-Fu on MGC-803 cell line. Methods The morphological changes of MGC-803 cells with AO/EB stain were observed under fluorescence microscope. The proliferation inhibition effeet was evaluated with MTT. The apoptosis induction effect was determined by FAM. Results The results of MTr array were as below: the difference was significant between Thai groups of 25 mg/L or above concentration and the control group (P＜0.05), 5-Fu of all testing concentrations showed significant difference compared with the control gToup(P＜0.01). For combined groups with the same concentration of 25 mg/L 5-Fu,combined groups showed distinct difference from the corresponding 5-Fu group (P＜0.01), but two combined groups showed no distinct difference with each other (P＞0.05). For combined groups with the same concentration of 5-Fu 12.5 mg/L, 5-Fu plus 50 mg/L or 100 mg/L Thai showed no distinct difference from 5-Fu group of 25 mg/L(P＞0.05). With FAM study, all test groups showed significant difference compared with the control group (P＜0.01). There was also significant difference between two test groups arbitrarily (P＜0.01).Conclusion Both Thai and 5-Fu could inhibit the proliferation and induce the apoptosis of MGC-803 cells.The effect is reinforced with the combination significantly. Combination with Thai could decrease the concentration of 5-Fu but have the similar effect.