The invention provides a method for determining senecionine alkaloid content in gynura segetum superfine powder. The method which is a high performance liquid chromatography method includes: using a C18 chromatographic column to perform separation, and using an evaporative light-scattering detector to perform detection, wherein chromatographic conditions include: filling agent octadecyl silane bonded silica gel; flowing phase is the mixture of acetonitrile and 0.2% phosphoric acid solution, and the volume percentage ratio of the acetonitrile to the 0.2% phosphoric acid solution is (15-25):(75-85); the flow rate of the flowing phase is 0.8-1.2ml/minute; the feeding volume of the evaporative light-scattering detector is 10 microliters; the temperature of a drift tube is 90 DEG C, and gas flow rate is 30psi. The method for determining the senecionine alkaloid content in the gynura segetum superfine powder has the advantages that the method is simple and easy to operate, and a reliable effective-component-content determining method is provided for the quality control of the senecionine alkaloid superfine powder.