To research the propagation characteristics of terahertz wave in sand and dust storms，based on Mie theory, the scattering characteristics of sand/dust particles are investigated for terahertz wave band, and the relationships of scattering efficiency factor, extinction efficiency factor and absorption efficiency factor with particle size and terahertz wavelength are obtained. The attenuation characteristic of terahertz electromagnetic wave propagation in sand and dust storms are calculated for sand and dust particles with log-normal size distribution. The research results show that the wave attenuation decreases with the increase of visibility of sandstorms and terahertz wavelength. From the numerical results of different sand weather at a wavelength of 40 μm, it is shown that sand-dust storm yields the highest effect for terahertz electromagnetic wave propagation, while the natural sand gives the lowest effect. The effect of low visibility sand and dust storms on terahertz wave propagation is obvious.