Objective To research the reversal effects of psoralen on multidrug resistant action and its influence on intracellular Ca2+ concentration in MCF-7/ADR cells and to explore its possible mechanisms of reversing multidrug resistance (MDR). Methods The inhibitory effects of psoralen on the viability of MCF-7/ADR cells were determined with MTT assay, intracellular adriamycin (ADR) concentration was assayed with HPLC and the intracellular Ca2+ concentrations in different incubative duration were detected with confocal microscope. Results Psoralen from 1 to 20 μmol/L reduced the value of IC50 of ADR in MCF-7/ADR cells, enhanced accumulation of ADR and influenced Ca2+ concentration with a negative correlation in different duration (24 h, 48 h and 96 h). Conclusion Psoralen can reverse MDR in MCF-7/ADR cells and its mechanism may be related to the increase of the intracellular accumulation of ADR by enhancing the intracellular Ca2+ concentration.