A new method of reference voltage vector acquisition that did not rely on motor’s parameter was proposed for the problem which the change of motor’s parameter could made the accuracy of reference voltage vector acquisition unreliable in the PMSM’s SVM-DTC method. The PI controllers were used for the error of torque and amplitude of stator linkage, and their output was separately allotted a weight. The weighted sum of their absolute value was used for the control of amplitude of reference voltage vector, and their ratio would be the gist that could compute the angle between reference voltage vector and stator linkage vector. The result of simulation showed that the performance of this method was favourable and the influence making by the change of motor’ parameters could be well overcame. The simulation verifies that the method was effective.