For linear textures, widely exist on 3D engineering surfaces, a method for characterization based on the spectrum analysis is proposed. Through an angular spectrum analysis of the power spectrum of 3D surface signals, the directional characteristic parameters of the linear texture distribution on the surface are extracted. By using the directional parameters, the engineering surface can be roughly identified. A texture detector based on the directional Gabor wavelet transformation is used to detect the texture signals. The linear texture features of different directions and scales on a complex engineering surface can be decomposed. A weighting multi-scale correlative analyzing method is presented. The correlation analysis results of the texture features of different scales are weighted according to the significance and summed to obtain the final correlation results. Through Laplacian differential operation of the correlative output, a sharper correlative peak is obtained. This method has been successfully used to extract and identify bullet marks.