For evaluating the effect of puddling on crop growth, comparative experiments have been carried out. Soils used in experiments were two paddy soils in Taihu Lake Region. Results obtained showed that puddling of clayey paddy soil, especially, of the soil with poor structure was beneficial to rice growth under pot experimental condition of no leaching: but she advantage of puddling disappeared under field condition. This may be due to that the efkct of puddling is concealed by leaching, fertilization, etc. of the soil under field condition. It was also found that the main reason affecting the growth of upland crop was the unharmonic regime among moisture, air and mechenical strength of puddled soil, which could not improved by mechenical approach when the soil water content was above plastic limits. It is suggested that drainage of the soil should be the only way to accelerate the aeration of the coil under this condition.