A method for a workpiece surface mass loss detection is presented based on wavelet transform. In order to obtain the surface morphology information, two-dimensional laser sensor is applied to measure the workpiece. The three-dimensional point cloud data obtained are analogous to the pixel point cloud in the grayscale image. The wavelet transform edge detection method is used to extract and locate the workpiece surface characteristics area and then to calculate the volume loss and mass loss on the surface of the workpiece. The detection experiment is performed for the damage on the surface of the steel material workpiece. The experiment for the steel material workpiece surface mass loss proves the feasibility of the solution. The results show that the tested workpiece damage quality detection accuracy can reach milligram level. The system is suitable for the measurement of big volume or big mass workpiece surface damage and evaluation of the material properties.