This paper presents an investigation of hyperthermia cancer therapy utilizing high-frequency magnetic field to induce a localized temperature increase on tumors by using superparamagnetic nanoparticles. In-vitro and in-vivo experiments showed the feasibility of hyperthermia cancer therapy. The relationship between temperature rise and cell survival rate was also investigated. While CT-26 colon cancer cells were heated above 45°C, the survival rate of cancer cells would be greatly reduced. A temperature increase as high as 59.5°C can be successfully generated in rat livers. In-vivo tests also indicated that hyperthermia cancer therapy using this approach could significantly suppress the growth rate of tumors by utilizing concentrated magnetic nanoparticles and temperature-sensitive hydrogel, which was used to secure the nanoparticles in the target tumor tissue. Furthermore, a feedback temperature control system was successfully developed to keep the nanoparticles at a constant temperature to prevent overheating in the tumors such that a safer and more precise cancer therapy is feasible. The developed technique may be promising for the hyperthermia cancer therapy.