OBJECTIVE:To establish a method for the content determination of AV45(the labeled precursor of PET agent for Aβ plaques)and its related substances. METHODS:HPLC method was performed on the column of Inertsil C18 with mobile phase of 50 mmol/L Disodium hydrogen phosphate solution- acetonitrile(containing 0.01% triethylamine)(15∶85,V/V)at a flow rate of 1.0 ml/min,the detection wavelength was 325 nm,and column temperature was 30 ℃,and volume injection was 20 μl. RESULTS:The AV45 and reaction intermediate as well as individual impurity peaks were well separated;the linear range was 200-1 000 μg/ml for AV45(r=0.999 2)and 20-100 μg/ml for intermediate(r=0.999 6);the detection limit and quantification limit of reaction in-termediate AV45 were 0.1 ng and 0.5 ng,respectively;RSDs of precision,stability and reproducibility tests were lower than 0.5%;recovery of AV45 was 98.93%-101.58%(RSD=0.69%,n=9). CONCLUSIONS:The method is simple and accurate with high specificity and good reproducibility,and suitable for content determination of AV45(the labeled precursor of PET agent for Aβplaques)and its related substances.