To make up for the blank of evaluation of vector control on DSP in servo control system, the performance analysis and evaluation are given based on the real-time requirements of vector control. The key modules of servo control and the properties of software and hardware in DSP are discussed, which lays the foundation of the work of evaluation. The CPU load is chosen as the performance index and the applicability of vector control is analyzed on specified conditions. Results of evaluation may have some reference value for the selection of vector control on DSP.