The invention provides a method for detecting non-specific esterase activity of aphids. The method includes isometrically mixing a substrate alpha-naphthyl acetate and a substrate beta-naphthyl acetate according to a ratio of 1:1 to obtain a mixed substrate, and preparing filter paper adsorbing the mixed substrate; collecting field population of the aphids, after homogenizing single-head aphids, dropping homogenate on the filter paper for color development, and comparing with a standard color palette, wherein the darker the filter paper develops, the higher the individual enzymatic activity is. By the method, resistance level of the field population can be judged by detecting individual non-specific esterase (NSE) activity. By comparing the individual color developed on the filer paper adsorbing the mixed substrate with the standard color palette, resistance individual frequency is acquired, and then population resistance level is known.