The optical properties of nonspherical dust aerosols in the wavelength range of 0.2~40 μm are calculated by combination of T-matrix method and an improved geometric optics under the conditions of representative shape distribution and size distribution. By comparing the optical properties of dust particles between nonspherical and isochoric sphere hypothesis. It is found that 1) the shape of dust aerosols has a smaller influence on the extinction efficiencical factor, scattering albedo and asymmetry factor compared to the size distribution; 2) the difference of phase function between nonspherical and spherical dust aerosols in the short-wave region is significant, especially in the visible region, and they change with different scattering angles; 3) in short-wave region, the extinction-to-backscattering ratio in the so-called lidar equation is affected by the shape of dust aerosols greatly, therefore, the nonspherical effects should be considered in the retrieval of dust optical thickness by using the lidar equation.