Soil water characteristic curve is an important parameter for studying soil water movement quantficationally. Now, generally soil physicists use van Genuchten model (shortened as VG model) to describe the curve (h-θ curve). How to determine parameters of the VG model was explored in this paper. Based on the data of soil negative pressure h and soil water content θ measured at the Luancheng Agricultural Ecosystem Station, Chinese Academy of Sciences, the nonlinear simulation function of MatLab was used to determine parameters of the VG model.The θ values calculated through the four-parameter model fitted quite well the measured θ values, with relatively limited error. Soil samples collected from the estuary of the Yangtze River were used to verify the findings, showing that the values calculated using the VG model, of which parameters were defined by the MatLab method. fitted the measured data quite well too with the norm of residual error square sum less than O.001.