Objective To prepare PET molecular probe folate-NOTA-Al18F(18F-FNA) and to explore its feasibility as an imaging agent in folate receptor positive KB tumor.Methods 18F-FNA was prepared by the method of aluminum fluoride coordination labeling, and the effect of phase transfer catalyst K2.2.2 on the labeling yield was evaluated.Biological distribution was carried out at 10, 30 and 90 min after injection of 3.7 MBq 18F-FNA in nude mice (n=20) xenografted with KB tumor, and the radioactive uptake (%ID/g) and T/NT ratios were then calculated in different organs or tissues.MicroPET imaging was performed at 40 min after injection of 18F-FNA (3.7 MBq).Results The labeling yield of 18F-FNA increased with the presence of K2.2.2.The radiochemical yield was above 98%.The radiochemical purity was above 99%, and still above 98% after maintained in PBS and FBS at 37 ℃ for 4 h.The biodistribution showed that the blood clearance of the probe was slow, and the uptakes in kidneys and tumor which overexpressed folate receptor were significantly high ((5.12±0.58) %ID/g and (1.37±0.20) %ID/g).The high radioactive uptake was observed in KB xenografted mice using microPET imaging.Conclusions The labeling yield of 18F-FNA could increase with the presence of K2.2.2.Furthermore, the encouraging biological distribution and microPET imaging results indicate that 18F-FNA may be a candidate for PET imaging in targeting folate receptor.