[Objective] The permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) has been widely adopted in industrial applications due to its excellent speed regulation performance and cost advantages. However, its further development is constrained by insufficient torque density. To enhance electromagnetic torque, the asymmetric rotor PMa-SynRM has become a research hotspot. Nevertheless, existing studies have failed to establish a quantitative relationship between the permanent magnet torque to reluctance torque proportion coefficient and electromagnetic torque enhancement capability, while also lacking systematic analysis of pole offset angle. Consequently, rapid evaluation of motor torque performance through torque proportion coefficient and pole offset angle remains challenging. To address this, this paper systematically investigates the impact of the torque proportion coefficient and pole shift angle on electromagnetic torque. [Methods] Based on these findings, this paper proposed an asymmetric rotor PMa-SynRM and evaluated its electromagnetic performance using the finite element method. [Results] The study revealed that as the torque proportion coefficient increases, the electromagnetic torque improvement initially rised and then declined, peaking when the ratio of permanent magnet torque to reluctance torque was 2. Furthermore, as the offset angle increases, the torque enhancement capability gradually strengthened. The results demonstrated that the proposed motor achieves a 7.82% increase in electromagnetic torque and a 57.73% reduction in torque ripple. [Conclusion] This study provides critical theoretical foundation for optimizing the torque performance of asymmetric rotor PMa-SynRMs.