An attempt is made to establish three statistical models for vertical distribution of atmospheric refractive index based on the theory and approach with the aid of conventional radiosonde record from the selected 20 stations in China. Results show that Ⅰ) the 4/3 equvalent earth′s radius model yields minimum accuracy and is applicable to within 1 km of the surface; Ⅱ) the modified version gives maximum accuracy; Ⅲ) the exponential model is effective in the lowest 3 km.