20(s)-ginsenoside Rg3 is extracted from traditional Chinese medicine, red ginseng. However, due to its poor aqueous solubility and low oral bioavailability, the use of 20(s)-Rg3 is limited. This study aimed to explore a method of preparing nano-sized 20(s)-ginsenoside Rg3 particle named 20(s)-ginsenoside Rg3-loaded magnetic human serum albumin nanospheres (20(s)-Rg3/HSAMNP) to change dosage form to improve its aqueous solubility and bioavailability. 20(s)-Rg3/HSAMNP were prepared by the desolvation-crosslinking method. The character of 20(s)-Rg3/HSAMNP was detected. An antiproliferative effect and cell apoptosis rates of 20(s)-Rg3/HSAMNP on human cervical cancer cells were determined by the MTT assay and flow cytometry, respectively. TEM analysis showed that 20(s)-Rg3/HSAMNP were approximately spherical and uniform in size. Thermodynamic testing showed that the corresponding magnetic fluid of a specific concentration rosed to a steady temperature of 42–65○C. Iron content was approximately 3 mg/mL. Drug encapsulation efficiency was approximately 70%. The potential of 20(s)-Rg3/HSAMNP combined with magnetic hyperthermia therapy to inhibit cell growth and induce apoptosis was much more prominent than that of the other groups. A new dosage form of 20(s)-Rg3 was prepared, which effectively induced apoptosis in HeLa cervical cancer cells in vitro when combined with hyperthermia.