The torque performance of the interior permanent magnet synchronous motor (IPMSM) has been widely concerned and studied for many years. This article focuses on the structure design and optimization of the IPMSM in the aircraft drive system, and aiming to improve the torque density and reduce the torque ripple. Firstly, the original structure of the IPMSM is given. And then, a fractional slot winding and ∇-type rotor magnetic pole topology are proposed as the optimized IPMSM structure in this article. In addition, the comparison of the original and optimized structure is studied by the simulation. Finally, the performance of an optimized prototype is analyzed by experimental test, and the validity of the design optimization method for proposed IPMSM structure is verified.