[Objective] In the deadbeat control of surface-mounted permanent magnet synchronous motor (SPMSM), the contradiction between the number of candidate voltage vectors and the computational burden limits performance optimization. This paper aims to propose a solution that balances control accuracy and real-time performance. [Methods] Taking SPMSM as an example, the following methods were proposed: (1) The n-th order subdivision method of the inscribed circle of the voltage vector hexagon was used to generate 6n2+1 candidate voltage vectors; (2) Simplified determination method 1 was employed, fixing the traversal count to 4 times; (3) Simplified determination method 2 was introduced, directly mapping the ideal voltage vector without traversal. [Results] Simulation and experimental results showed that the 8th order subdivision method (385 candidate vectors) reduced torque ripple by 12.87% and flux linkage ripple by 30.67%; simplified determination method 1 and simplified determination method 2 reduced computational time by 42.86% and 87.94%, respectively. [Conclusion] The proposed method achieves arbitrary expansion of candidate vectors and significant reduction of computational load, providing a reference for optimizing the performance and real-time capability of deadbeat control.