Simulation of movement and degradation of acaricide NC13292 in a clay-loamy soil was condcuted with the CALF model in comparison with the measurements in the field.when only using the adsorption coefficient, the migretion rate of the acaricid of the simulation.vas greater than that of measurements after a period.It implies that the movement of a chemical in soil could be two process.One is a partitioning process of a chemical between solid phase and water phase, which dominates the movement of a chemical in soil.The other is a diffusion process, which is significant only in a granular structured or clay soil, particular for polar compounds.When the empirical diffusion rate constant (0.0125/day) was used, the simulated movement of NC13292 in the soil is quite well close to the measurement in the field.