It has been documented that calycosin induces anticancer effects against a wide range of cancer cells, in vitro. However, pharmacokinetic characteristics of calycosin based on its interaction with albumin as a main carrier protein as well as corresponding anticancer mechanisms remain largely unknown. Herein, we inquired into the interaction of calycosin with human serum albumin (HSA) by a wide range collection of spectroscopic and theoretical data. Also, anticancer effects of calycosin on breast cancer cells, MDA-MB 231, were explored by cell viability, lactate dehydrogenase (LDH), caspase-3 activity, and real-time PCR assays. The findings demonstrated that the quenching process resulting from the interaction of calycosin and HSA was largely static in nature and that the calycosin-HSA system spontaneously forms. Cellular and molecular studies revealed that calycosin did not induce a significant cytotoxic effect on the viability of normal human breast epithelial cells, (MCF-10A), even at 200 μM concentration at which it was able to inhibit the proliferation of breast cancer MDA-MB 231 cells up to 50%. Then, it was disclosed that calycosin can disrupt the membrane integrity and induces apoptosis in MDA-MB 231 cells through overexpression of caspase-3 mRNA, down regulation of Bcl-2, and elevation of caspase-3 mRNA and activity mediated by downregulation of mTOR and Akt mRNA. Therefore, it was realized that in breast cancer MDA-MB 231 cells, calycosin is able to suppress cellular proliferation via apoptosis, which is controlled by the Akt/mTOR signaling cascade.