Vector control holds an important position in the field of speed adjustment system of induction motor because of its outstanding performance. However, the speed sensor fixed on the shaft of the motor will reduce the robustness of the system as well as increasing cost and complexity. Traditional three-level space vector modulation algorithm will restrict the performance of the system indirectly because of the massive triangular and square root computation it contains. A vector control system based on current model flux observer and MRAS speed identification under 120°coordinate SVM algorithm has been proposed in this paper. The validity of the system has been analyzed by theoretical modeling and been proved by simulation and experimental test.