The detection efficiency of soil samples in a cylindrical measuring geometry was calculated using the Monte Carlo method, evaluating the self-absorption corrections in the energy range of 46-2615 keV. By controlling variables, the effects of parameters such as sample density, height and humidity on the self-absorption factor have been studied, and the corresponding correction functions have been obtained. The research results show that: for γ photons of a specific energy, the change of sample density has the greatest impact on self-absorption. For samples whose density is not much different from that of the standard sample, the impact of changes in height and humidity on self-absorption should be considered. In the high-precision measurement of samples containing low-energy γ-photon radionuclides, the errors caused by density, altitude and humidity should be comprehensively considered.