For testing the determination of the reactivity of aluminum powders it is proposed to use the following parameters: temperature of the beginning of oxidation, maximal oxidation rate, degree of transformation (degree of oxidation) of aluminum, relative thermal effect. Parameters for an evaluation of the reactivity of powders were chosen following the analysis of results of a non-isothermal oxidation of powders of different grain size under conditions of programmed heating (the oxidizer being air). According to the proposed method of testing, the sample of ultrafine powder UFAP-4 produced by the electrical explosion of wires has the highest reactivity among the studied powders.