In order to study the fire extinguishing capacity and the corrosion problem of the fire extinguishing aerosols in engineering application, experimental comparison for the formulation of the fire extinguishing aerosols between K type and S type was carried out in this paper. Taking strontium salt as the main oxidant and potassium salt as the supplement, several formulations were designed and optimized. From the results of the extinguishing concentration, spray time, Cu board color change and other performance parameters, it can be seen that the best performance is obtained when the ratio of Sr(NO^₃)^₂ to KNO₃ is 1.4：5.0. Its fire extinguishing efficiency is 95 g/m3, spray time is 42 s, and Cu board has no obvious turned green, which not only ensures the aerosol extinguishing ability, but also provides a good way to solve the corrosion problem.