To reduce the switching frequency of the traditional three-level permanent magnet synchronous machine (PMSM) model predictive control (MPC) system, a three-level MPC method for PMSM based on subregion switching frequency optimization is proposed in this paper. First, the space voltage vector plane is divided into 12 sectors, and the voltage vectors in adjacent sectors are selected as candidates according to their positions at the previous time. Then, the restriction on switching state is added, so that only one phase switch is allowed to be changed continuously in each switching period, which can effectively decrease the switching frequency while reducing the number of candidate vectors. Furthermore, the midpoint potential balance can be achieved by utilizing the negative and positive redundant small vectors that have the same space position but exert opposite effects on the midpoint potential. Finally, both simulation and experimental results verified the effectiveness of the proposed control strategy.