Abstract: The filter paper method,osmotic method and vapor phase technique for measuring soil suction were introduced.The soil water characteristics curves of the typical Shanghai soil(layer ②1) in a suction range of 0～1400 kPa and a full suction range were obtained using these three lab techniques.From the soil-water characteristic curves obtained,it is clear that,the air-enter value for the testing soil is about 110～250 kPa,the residual saturation degree value is about 20 MPa,the SWCC for desorption process of Shanghai soil shows clearly in step-phase,and for the lower suction range(0～1400 kPa),the soil water characteristics curves for Shanghai soft clay shows significantly in hysteretic loop.