Despite medicinal advances, cancer is still a big problem requiring better diagnostic and treatment tools. Magnetic nanoparticle (MNP)-based nanosystems for multiple-purpose applications were developed for these unmet needs. This study fabricated novel trifunctional MNPs of FeO@PLA-PEG for drug release, MRI and magnetic fluid hyperthermia. The MNPs provided a significant loading of curcumin (∼11%) with controllable release ability, a high specific absorption rate of 82.2 W/g and significantly increased transverse relaxivity ( = 364.75 mM s). The study confirmed that the MNPs enhanced MRI contrast in tumor observation and low-field magnetic fluid hyperthermia could effectively reduce the tumor size in mice bearing sarcoma 180. The nanocarrier has potential for drug release, cancer treatment monitoring and therapy.