In order to improve the efficiency of scanning and the quality of parts forming, a driving system based on SOPC system for 3D printer was built and a 3D printing scan path optimization algorithm based on velocity orthogonal decomposition was proposed. The system could support the synchronous drive of each axis. The algorithm combined the advantages of orthogonal decomposition principle and synchronous drive mode, the empty stroke and straight corner in the scanning path were replaced with the circular curve, so that the velocity of each axis could change evenly, and the print head moved at a uniform speed according to the planned path at the maximum feasible velocity to scan and fill the whole section. The experimental results show that compared with the original algorithm, by using the new algorithm, the scanning time reduces by more than 10%, especially when the model with complex scanning structure and relatively small area is printed, the scanning time can be reduced by more than 55%.