Abstract: Objective Through detection drug resistance gene expression and development of drug sensitivity to provide clinical personal chemotherapy. Methods We choose 50 lung tumor patients in 2008-2009 from the affiliated hospital of Inner Mongolia medical college. Thirty-two cut off by surgery, 18 from bronchoscopy. MTT assay was employed to determine the drug sensitivity. The expression levels of drug resistance genes were detected by immunohistochemistry. Results (1) The expression rates of MRP1, P-gp, and Topo II genes in the 50 cancer tissues (but 10 tissues were contaminated) were 72. 5% (29/40), 67. 5% (27/40) and 50. 0% (20/40), respectively. The expression rate of MRP1 in the adenocarcinoma, squamous and small-cell lung cancer 76. 2%, 80%, 55. 6%, but the expression rate of P-gp and TopoⅡare 80. 9%, 80%, 22. 2% and 42. 9%, 60. 0%, 55. 6%, respectively. No significant statistical difference was observed in the expression of MRP1, P-gp, and Topo II between human adenocarcinoma and squamous cell carcinoma (P > 0. 05), but a significant statistical difference was found in P-gp expression between human adenocarcinoma or squamous carcinoma cell and small-cell lung cancer (P < 0. 05). (2) A significant positive correlation was noted between MRP1 expression and the development of resistance to cisplatin, gemcitabine and vinorelbine (P < 0. 05), but no significant correlation was observed between MRP1 expression and the development of resistance to paclitaxel and ifosfamide (P > 0. 05); A significant positive correlation was observed between P-gp expression and the development of resistance to the studied drugs, namely, cisplatin, gemcitabine, vinorelbine and paclitaxel (P < 0. 05), however, no significant correlation was found between P-gp expression and the development of resistance to ifosfamide (P > 0. 05); The positive correlation expression of TopoⅡ and the degrees of chemoresistance to the cisplatin, gemcitabine paclitaxel and iphspamide were significant, respectively (P <0. 05), but there is no significant difference in the drug tolerance of vinorelbine (P > 0. 05). Conclusion Lung cancer resistance is the role of many drug resistance gene.