Abstract： Objective： To observe the effect of gambogic acid(GA) combined with icotinib on the proliferation of non- small cell lung cancer(NSCLC) H1975 cells that is resistant to epidermal growth factor receptor-tyrosine kinase inhibitors(EGFR-TKI)，and to discuss the possible mechanism of GA in reversing drug resistance. Methods：The EGFR- TKI resistant H1975 cells were established by sustained induction， and effects of the simple use of icotinib or GA and the combined use of the two on the proliferation of the drug-resistant H1975 cells were detected by MTT assay；Annexin V-FITC / PI double staining was used to detect the effect of drug treatment on apoptosis in drug- resistant H1975 cells； Transwell assay was performed to detect the effect of drug treatment on the migration of drug-resistant H1975 cells；the effect of drug treatment on the protein expression of drug-resistant H1975 cells was determined by Western blot assay. Results：①The inhibitory effect of simple application of GA or icotinib on the proliferation of drugresistant H1975 cells showed a concentration dependent manner， that is， the higher the drug concentration，the stronger the inhibitory effect. The inhibitory effect of GA combined with icotinib on the proliferation of drug-resistant H1975 cells was significantly stronger than that of icotinib alone(P＜0.05). ②There was no significant difference being found in the comparison of the induced apoptosis of drugresistant H1975 cells between the group with the simple use of GA or icotinib and the blank group(P＞ 0.05)； the combined use of GA and icotinib could effectively promote the apoptosis of drug- resistant H1975 cells， and the effect was significantly better than that of simple drug treatment(P＜0.05). ③The simple use of GA or icotinib had no significant effect on the migration of drug- resistant H1975 cells(P＞ 0.05)，and GA combined with icotinib could effectively inhibit the migration of drug-resistant H1975 cells， and the effect was significantly better than simple drug treatment(P＜0.05). ④The protein expressions of phosphorylated epidermal growth factor receptor(p-EGFR)，phosphorylated protein kinase B(p-AKT)，and phosphorylated extracellular signal-regulated kinase(p-ERK) in the GA plus icotinib group were significantly lower than those in the blank group， the icotinib group and the GA group(P＜0.05). Conclusion： GA combined with icotinib can effectively inhibit the proliferation of EGFR-TKI resistant H1975 cells，and inhibit cell migration，induce cell apoptosis，and play a reverse role in EGFR-TKI resistance of lung cancer，and the specific mechanism may be related to the inhibition of EGFR signaling pathway molecule phosphorylation and the regulation of protein expression.