Abstract: Recently, vernier permanent magnet machines (VPMM) based on multiple flux density harmonics attract worldwide attention. Under the same electromagnetic loading, the torque density is nearly twice that of conventional PM synchronous machines. However, most of the novel topologies are advanced by iteratively optimizing the structural dimensions of the existing topologies, which leads to the solidification and coupling of flux density harmonics, making it tricky to fully exploit the torque ability under unit flux density and further enhance torque density. This article proposes a topology orientation construction method for high-torque density VPMMs. Based on the air-gap permeance unit model, harmonic analysis and flux analysis approaches are proposed, which provide the quantitative and intuitive illustration of the generation of average torque. Moreover, methods for enhancing the torque ability of multiple flux density densities are studied, and topology orientation construction technique is then proposed, providing theoretical basis and support for improving the torque density and exploring the upper limit of torque capability per unit flux density. Finally, two VPMMs are constructed, and the detailed electromagnetic performance analysis is conducted. Then, a prototype is made and tested, confirming the correctness and effectiveness of the design and analysis results.