Herein, the water-soluble C60-COOH derivative was first obtained through Bingel cycloaddition reaction of C60, and then the MnO2 nanoparticles were loaded on it by hydrothermal reaction. Finally, the tumor targeting molecule folic acid was conjugated with the aminated polyethylene glycol to synthesize the multifunctional nanocomposite C60-Mn-PEG-FA. Its structural composition and good water dispersibility was confirmed by FTIR，UV-Vis, XPS and DLS. In vitro experiments, the results demonstrated that C60-Mn-PEG-FA could not only achieve magnetic resonance imaging (MRI) at low pH, but also improve hypoxia. At a low concentration of 40 ?g/mL and exposed to natural light of 100 mW/cm2 for 5 minutes, it could target and kill 82% tumor cells without damage to normal cells, providing a strategy for the design of novel theranostic agents.