Abstract: Characteristics of chemical loss in loam and sand containing a certain initial chemical were investigated experimentally through soil testing in laboratory. The process of ponding water on soil surface before runoff was considered. It was found that with both surface runoff and subsurface drainage, only a small part of the lost chemical of soil was in the surface runoff water while most lost chemical of soil was in the subsurface drainage water at the same situations. So about reducing subsurface drainage to enhance the utilization of the chemical of soil should be considered at first if methods was not adopted that reduce surface runoff water and subsurface drainage water at the same time. And within the intensity of rainstorm, the greater rainfall intensity, the less initial water content of soil, the better condition of subsurface drainage and the coarser sandy soil, the more chemical mass loss to surface runoff and subsurface drainage water, which reduces chemical efficiency of soil. The results will provide significant references for the improvement of the utilization of the chemical of soil and the reduction of agricultural pollution.