In order to obtain new energetic materials with high energy, low sensitivity and easy storage, TKX-50/AP cocrystal samples were successfully prepared by spray drying method. The effects of different feed rates on the morphology of the samples were investigated, and the optimum process conditions were obtained. SEM shows the sample was ultrafine spherical particles with sphericity of Φ = 96.4 % and d50 = 1.33 μm; EDS results show that the microspheres have the characteristic elements of both. XRD and FT-IR shows the crystal structure and molecular structure are different from raw TKX-50 and AP, the formation of TKX-50/AP ultrafine cocrystal was confirmed. TG-DSC shows the cocrystal exhibits different thermal properties from the mixture, there is only one strong exothermic peak at the heating rates of 10, 15 and 20 K/min; Compared with the mixture of TKX-50 and AP, the impact sensitivity and hygroscopicity of the cocrystal sample decreased by 40.7% and 37% respectively, showing remarkable safety performance.