Wilting is one of life features of plants responding to drought stress. Early identification of plant wilting is of importance for effective use of water in crop production. For this purpose, a laser scanner based on the principle of triangulation project was used to obtain 3D images of plants and the DC component of 2DFT was extracted as a wilting index. Four species, including zucchini, gourd, pumpkin and okra, were tested. The experimental results demonstrated that this index could identify the early wilting for each species and has a good linear correlation with the wilting degrees (R2＞0.82). In addition, the statistical models of multiple linear regression, which relates the wilting index to DVPD and the solar effective radiation, was proposed; and it can be used as the qualitative index of plant water deficit stress degree.