A method for the detection of nucleoside phosphorylase activity is established, which has solved the problem that the quality of industrial phosphorylase can not be determinedThe reaction system of nucleoside phosphorylase is established to make inosine under the action of phosphorylase to generate inosinate disodium(IMP) with 10 g/L inosine and 10 g/L sodium tripolyphosphate as the substrates, the optimal reaction temperature is 40 °C, pH is 4.5, and the reaction time is 10 min.The production quantity of IMP is determined by high performance liquid chromatog.(HPLC).The chromatog. conditions are as follows: C18 column, with 0.02 mol/L monopotassium phosphate and acetonitrile of 99.5:0.5(V/V) as the mobile phase, 1 mL/min gradient elution, 40 °C, UV detector(λ=254 nm), and 2 μL sample volumeThis method is accurate, the recovery is more than 99.5%, and the RSD is less than 0.5%.The establishment of detection method for nucleoside phosphorylase activity can accurately determine the product indexes of enzyme solution, accurately calculate the enzyme additive amount, and solve the problem that the end point of enzyme catalytic reaction can not be determined