Abstract: The synthesis, preliminary biological evaluation and PET/CT and MRI imaging results of a potential PET/MRI dual-modal imaging tumor probe, ⁶⁴Cu-DOTA-SPIONs-PEG-FA, used for targeting folate receptor-positive cancer, have been reported in this investigation. This probe was composed of a superparamagnetic iron oxide nanoparticles(SPIONs) coated with the biocompatible polymer poly(ethylene glycol)(PEG), folic acid, 1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid(DOTA) and positron-emitter copper-64. This radioactive probe has high radiochemical purity(greater than 98%) after purification. The bio-distribution in the nude mice bearing KB cells tumor shows that ⁶⁴Cu-DOTA-SPIONs-PEG-FA has a higher uptake in liver, spleen and lung, respectively, and has an obvious-effect of active targeting toward the KB tumor in contrast to ⁶⁴Cu-DOTA-SPIONs-PEG-OH. Under the modes of both MRI and PET/CT, the KB tumor can be observed clearly. As a PET/MRI dual-modal imaging tumor probe, ⁶⁴Cu-DOTA-SPIONs-PEG-FA is worthy to be further studied to improve its labeling yield, stability, specific activity and so on.