The present invention relates to a method of sensing aerosol characteristic parameters using dual-wavelength light scattered signals and the application thereof, and belongs to the technical field of fire warning. The method procedures include measuring the scattered light power of two different wavelengths, calculating the surface area concentration and the volume concentration of aerosol, and obtaining the Sauter mean diameter of the aerosol the surface area concentration, the volume concentration and the aerosol Sauter mean diameter are compared with corresponding thresholds, and then corresponding fire alarm signals are emitted. By the adoption of the method, on one hand, the particle size of an aerosol can be judged according to the Sauter mean diameter, so that whether a fire really occurs can be identified in time and a fire alarm signal or a non-fire factor interference prompt signal can be emitted timely and correctly; and on the other hand, the characteristic parameters of the aerosol can be obtaine
