Through the introduction of the existing problems of texture mapping process for laser machining of 3D surface, the necessity of STL model optimization is described, and re-sampling algorithm of optimization has been roughly divided into the following three steps: re-sampling point calculation, triangular patch re-sampling and mesh vertex deletion. The practicability and feasibility of the approach to re-sample STL model has been verified. The algorithm can make most of STL models optimized and assure the accuracy of texture mapping for laser marking of 3D surface.