Effect of the drainage on the melioration of soil moisture condition of paddy field for winter crops was studied in field plots.The soil investigated was a slightly acid,silty clay loam,derived from lacustrine deposit in Tongting Brigade,Wusi,Kiangsu.The land was used under a rotation of three crops in one year rice-rice-winter crops (mainly wheat),with a total yield of about 15 tons per hectare.A wet surface soil in rainy spring usually restrained the good growth of wheat plants.The ground water often rised up to the soil surface after a daily rainfall above 50 mm.