The mode of genesis of plate-like structure of soils under different conditions may be different.Broad field observation reveals that soils favoring plate-like structure formation generally have an easy access to an abundant but intermittant supply of water,low content of raw or ganic matter as well as of humus,indefiniteness but not being too sandy in texture,and weakness in structural stability.The present paper reports the evidences gathered from the field observation and laboratory experiments showing that plate-like structure can be developed through the effect of alternate wetting and drying processes.Laboratory experiments have shown that the degree of perfection of the development of plate-like structure as evidenced both from the horizontal natural crackings and from the volume of swelling of the soil body increases with increase in the number of cycles of alternate wetting and drying.(PlateⅠ) In order to assure the efFectiveness of the processes,both drying and wetting should be carried out as thorough as possible.