This paper mainly introduced the technique of serial digital images for analyzing pore characteristics on a small scale.Soil samples are impregnated by resins containing fluorescent dye,and grinded consecutively at an interval of 1 mm in order to obtain the serial images of pore space.By using this technique, we analyzed pore characterist ics on a small scale from a cultivated soil from USA and a cultivated soil from France,and the results showed that there were differences in image pore area,image pore size,image pore variability,pore connectivity,pore overlapped extent and pore circulating ability in those two soils, which were considered to be related with their different organic material contents.