Abstract: The atmospheric refractivity gradient near the ground is an important factor that affects the performance of radio systems. In order to study the relationship between refractivity gradient and ground meteorological parameters, we used the radiosonde data from 1986 to 1995 in Taiyuan to fit the relationship model between the near-surface refractivity gradient and the ground meteorological parameters. By fitting the sounding data, the results show that the linear relationship between refractivity gradient in the lowest 1 km near the ground and ground parameters is better than the exponential relationship with the ground refractivity in Taiyuan area, and meanwhile, the height of refractivity gradient affected by ground temperature, humidity and pressure can be directly seen from the relationship model of ground meteorological parameters. By studying the statistical relationship between refractivity and ground meteorological parameters, we can evaluate the radio line-of-sight near the ground more quickly through the ground temperature humidity and pressure, and the study in this paper can provide further support for the study of atmospheric refraction and for the optimization of radio system planning and design.