Abstract: ［Abstract］Objectives　99mTc-methoxyisobutylisonitrile （MIBI） SPECT imaging technology was used to observe the condition of tumor cell in-taking imaging agent in the C57BL/6J mice Lewis lung cancer model before and after using Ginsenoside Rg3 （short for Rg3）.We aimd so as to discuss the feasibility of using this method to evaluate tumor multidrug resistance（MDR）status. Methods　Mice Lewis lung cancer models were randomly divided into Rg3 group and the control group. After applying Rg3， semi-quantitative analysis was made on 99mTc-MIBI SPECT imaging and region of interest（ROI） to observe the multidrug resistance state of tumor and then the results were compared with the detection results of flow cytometry. Results　The tumor intake ratio（T/N）difference between the control group and the Rg3 group in imaging， imaging before applying Rg3 and imaging after applying Rg3 were separately 15， 60 and 120 min．The differences were statistical significant（P < 0.01）. The eliminate indexes（WR）of the control group and Rg3 group were positively related to P-gp protein expression positive cells detected by flow cytometry（P < 0.05）. Conclusions　99mTc-MIBI imaging is negatively related to P-glycoprotein （P-gp） expression in mice Lewis lung cancer cells，which can clearly show the multidrug resistance state of tumors and dynamically monitor the effect of Rg3 on multidrug resistance reversion of mice Lewis lung cancer.