Abstract: Objective To explore the expressions of P-gp,MRP1,LRP and GST-π in patients with advanced laryngocarcinoma in tumor tissue before and after radiotherapy,and the effect of radiotherapy on laryngocarcinoma drug resistance gene. Methods Immunohistochemical method was used to detect the expression intensity and distribution of P-gp,MRP1,LRP and GST-π in 76 cases with advanced laryngocarcinoma before and after radiotherapy. Results Laryngocarcinoma has primary drug resistance,in different pathological types of laryngocarcinoma tissues,P-gp shows strong positive expression with high intensity,there was significant difference with the other three multidrug resistance proteins(F=8.0839,P=0.0438).The positive expression rate of MRP1 in different pathological types of laryngocarcinoma tissues had significant difference (t=9.575,P<0.001),after radiation therapy,the positive expression rate of P-gp,MRP1,LRP and GST-π has increased,the expressions of P-gp and MRP1 had significant difference (P<0.05). Conclusion The expressions of P-gp,MRP1,LRP and GST-π in laryngocarcinoma are different,radiation can cause over-expressed laryngeal resistance gene protein,has influences on the formulation of laryngeal carcinoma chemotherapy.