Abstract: Field γ-ray spectrometry is an efficient, accurate and economical way in geological exploration and measurement of ionizing radiation environment. It was mostly influenced by soil moisture in field measurement process. Different soil moisture correction coefficients can be got when a numerical model was established and the attenuation coefficients of mass and line were calculated based on the γ-ray attenuation law in soil. Contents of uranium, thorium and potassium were measured by four-channel γ spectrometer under different soil moistures in the same soil location. The correction value calculated from previous correction coefficient was compared with that of the HPGe spectrometer measurement. The results show that the effects of soil moisture for on-site γ-ray spectrometry can be reduced after correction by numerical simulation.