Abstract: By testing and analysing saturated water conductivity，water characteristic curve and water constants in sandy soil with different organic matter contents，the relationship between sandy soil organic matter and hydrodynamic parameters is studied．The results show that there are linear relationships between sandy soil organic matter and water parameters：the higher the soil organic matter content，the greater the soil water content under same soil water suction；there is a very remarkable negative linear relationship between the soil saturated water conductivity and the soil organic matter content and < 0.O1 mm physical clay：the soil organic matter is the most important influence factor on soil hydrodynamic parameters in sandy soil．