The diffusion amounts of phosphate in soils at varying time were determined byhalf-cell technique using 32P. Five kinetic equations were used to fit the dynamicprocess of phosphate diffusion in the soils. It was found that parabolic diffusionequation was the best model to describe the process. The temperature quotient (Q10) ofPhosphate diffusion in the soils at 20% water content was 1.2 or so, which was inagreement with that diffusion is a physical process. The activation energy (EDa) ofphosphate diffusion in soils, calculated by Arrhenius equation, decreased withincreasing soil moisture and varied from 12 to 34 kJ / mol with an average value of25kJ / mol under low water tension range (< 105 Pa), which was close to theactivation energy of nutrient ion diffusion in solution. Therefore, it was suggested thatthe phosphate diffusion in soils at low water tension condition occurred mainly in theliquid Phase. Moreover, the absolute reaction-rate theory was transplanted and used toinvestigate the diffusion process in soils. The parameters, net activation energy,activation entroPy, activation enthalpy and activation free energy of phosphate diffusionin soils, were derived from the theory. The results showed that these parameters inthe four soils at the same water content changed in the similar to EDa, which indicatedthat the parameters could be used to describe the energy characteristics of Phosphatediffusion in soils.