Abstract: Objective To the effect of verapamil on chemosensitivity of human esophageal squamous cell carcinoma cell lines and to investigate the relationship between the resistance of verapamil to reverse and P-gp. Methods The IC₅₀ values(IC₅₀1) of three kinds of chemotherapy drugs: Adriamycin, cisplatin, and 5-fluorouracil were detected by CCK-8 method in 2 kinds of esophageal cancer cell lines ( KYSE-150 and KYSE-510). Each cell was processed by verapamil (4.91 μg /mL) combined with the chemotherapy treatment above, IC₅₀(IC₅₀2) value was detected by CCK-8 assay combined with chemotherapy for the verapamil of the 2 esophageal carcinoma cell lines (KYSE-150 and KYSE-510) . Real-time PCR was used to measure the expression of multidrug resistance genes hMDR1 in various treatment groups of esophageal cancer cells. Expression of P-glycoprotein in esophageal cancer cells in each treatment group by Western bolt method. Results The IC₅₀ values of adriamycin and cisplatin in KYSE-150 cells 7.33±0.67, 3.23±0.06 were both less than that in KYSE-510 cells 11.57±0.98, 17.25±0.08, while the IC₅₀ values of 5-fluorouracil in KYSE-150 cells 24.33±1.67 was significantly higher than that in KYES-510 cells 14.67±1.02. After adding verapamil, the IC₅₀ values of Adriamycin, cisplatin and 5-fluorouracil in two esophageal cancer cell lines (KYSE-150 and KYSE-510) all decreased to different degrees, and the above three kinds of chemotherapeutic drugs had increased their sensitivity to varying degrees. Among them, the cisplatin group before adding verapamil had different degrees of resistance compared with KYSE-150 cells and KYSE-510 cells. After joining verapamil, IC₅₀ value change for the KYSE-510 cells multiplied for 4.7 times, suggesting that the reversal was sensitive; IC₅₀ value change for KYSE-150 cells was 1.84 times smaller, suggesting that the reversal was tolerant. The expression of hMDR1 / P-gp in each cell group did not change significantly before and after the application of verapamil. Conclusion Tip the KYSE-510 cells (DDP) sensitivity to the reversal of verapamil, and KYSE-150 cells (DDP) reverse resistance of verapamil. Verapamil reverses drug.