Purpose To prepare 68Ga-NOTA-SPIO as PET/MRI dual mode imaging probe with high sensitivity and resolution,and further evaluate its in vitro and partly in vivo biological properties.Materials and Methods The precursor SPIO-PEG2000-NOTA was prepared and characterized.The precursor was radiolabeled by using one step method to prepare 68Ga-NOTA-SPIO as dual mode imaging probe.The labeling rate of the probe was determined by rapid thin-layer chromatography.Besides,the in vitro stability and lipid water partition coefficient of the probe were evaluated,and its biodistribution in normal mice was also observed.Results The precursor SPIO-PEG2000-NOTA with uniform dispersion and uniform particle size was prepared,and the dual mode probe 68Ga-NOTA-SPIO was synthesized.The labeling rate reached 99％,and the lipid water partition coefficient (Log P) was (-2.60±0.13).The radiochemical purity of the probe was higher than 95％,as it was incubated in the phosphate buffer and fetal bovine serum within 2 hours.The probe was mainly distributed in the liver and spleen of mice,and its clearance velocity in blood was fast.Conclusion The double mode probe 68Ga-NOTA-SPIO synthesized by one step method has high labeling rate with no need of purification,which has good physic-chemical properties and biocompatibility.The probe can be used in the further research of PET/MRI dual modality imaging.