Based on the expressions of flux and torque of surface permanent magnet synchronous motor (SPMSM) direct torque control (DTC) system using the amplitude of applied voltage vector as the variable, the values of stator flux and torque at the next sampling point after applying voltage vector with different amplitude were given. The object function of flux error and torque error was proposed. The predictive control would select the optimal amplitude of voltage vector to minimize the object function. Simulation results showed that the PMSM DTC system under the control of proposed strategy worked properly. As the predictive control selected the optimal voltage vector from aggregate of voltage vectors, more voltage vectors would lead to better control performance, at the cost of heavier calculation burden. Control performances of SPMSM DTC system were given using 9 methods of dividing voltage vectors. According to control performance and calculation burden, dividing voltage vectors into three equal parts was an ideal way.