OBJECTIVE： To study the effect of peiminine on increasing the chemosensitivity of 5 kinds of cancer cells. METHODS： Using human esophageal cancer Eca-109 cell， human breast cancer MCF-7 cell， human small cell lung cancer A549 cell， human hepatoma HepG2 cell and human cervical cancer HeLa cell as objects， MTT colorimetric method was used to detect the growth inhibition rate of above-mentioned 5 kinds of cancer cells after treated by peiminine with maximal non-toxic mass concentration （20 μg/mL） and adriamycin with different gradient mass concentrations （0.026-2.1， 0.026-2.1， 0.125-2.0， 0.125-2.0， 0.062 5-0.10 μg/mL） for 72 h. The half inhibitory concentration （IC50） was calculated. Crystal violet staining method was adopted to observe the proliferation of above-mentioned cancer cells after treated by peiminine with maximal non-toxic mass concentration and adriamycin with low mass concentrations （0.02， 0.005， 0.04， 0.02， 0.01 μg/mL） for 7 d. Solvent control， single use of peiminine and adriamycin control were conducted. RESULTS： Compared with single use of adriamycin， the combination use of peiminine and adriamycin can improve the growth inhibition rate of 5 kinds of cancer cells to certain degree， most of the differences were statistically significant （P＜0.05 or P＜0.01）； and IC50 was obviously decreased， with statistical significances （P＜0.05 or P＜0.01）. Compared with solvent control， single use of peiminine or adriamycin had no obvious effects on the proliferation of above-mentioned cancer cells in 7 d， and the combination use of peiminine and adriamycin can obviously inhibit the proliferation of above-mentioned cancer cells in 7 d. CONCLUSIONS： Peiminine can enhance the sensitivity of above-mentioned-mentioned 5 kinds of cancer cells to certain degree， showing certain chemosensitivity increasing effect.