Abstract: Objective:The purpose was to study the absorption of alkaloids from Rhizoma Coptis by HepG2 cells and their effect on the expression of Mitochondrial Complex Ⅲ. Methods:HepG2 cells were grouped by control, jatrorrhizine, protoberberine, coptisine, palmatine and berberine, with concentrations from high to low (0.25、0.50、1.00、2.00、4.00μg/mL) for 24h.HPLC was used to detect concentration of alkaloids in cellular, and Western blot was used to study alkaloids’ function on Mitochondrial Complex Ⅲ. Results:It was found that at the same concentration, HepG2 cells could absorb berberine more easily, followed by coptisine, jatrorrhizine could not be absorbed. Besides, berberine and coptisine could enhance the expression of Mitochondrial Complex Ⅲ. Conclusion:The experiment showed that berberine and coptisine could cure Diabetes and Diabetic complications, while other alkaloids effect slightly.