Corn root is separated into a series of root elements. According to the statistical measured parameters, the random 3-D model of corn root was constituted based on coordinate transformation. In the model building, the measured data was fitted to NURBS curve, shape and surface of the model were expressed by NURBS curve and NURBS surface respectively. Matlab and 3-D CAD software were used as main tools. The model was saved in IGES file format which can be import into 3-D CAD software and FEA software for further analysis of mechanical properties of the corn root. The corn root modeling method is different in principle from the other existed methods and has great significance for mechanical analysis of the root system in the crop root treatment, plants reinforcement of soil and etc.