Based on the HITRAN2012 database,the variation of complex refractive index of sand dust in the terahertz bands was obtained by using the method of cubic spline interpolation.Using the Mie theory,scattering properties of sand particle with different sizes illuminated by the terahertz wave were analyzed.Propagation characteristic of terahertz wave in weak sand dust atmosphere condition was investigated,where only single scattering effect was considered due to the low volume ratio of the particles.The results show that the scattering intensity distributions of the sand particle in the range of 1 THz to 4 THz depend mainly on the size parameter of the sand particle.For small particles,the backscattering efficiency increases monotonically with the increase of the size parameter.While big oscillation was found for particle with large size parameter.In different sand atmosphere conditions characterized using different size distributions of sand dust,the statistic extinction efficiency increases as the increase of the frequency.This paper provides useful reference for the application of terahertz wave in emergence communication,atmosphere monitor,and detection of sands.