In order to meet the requirements of a certain type amphibious aircraft of the wind tunnel test, 5 sets 12 of kW permanent magnet AC servo motors were designed. The motor was adopted by magnetic circuit analysis method and finite element analysis simulation, which were characterized by high power, small size and high speed. The ground debugging results show that the simulation results of electromagnetic design software are basically in agreement with the debugging results, and the power density of the developed motor reaches 2.0 kW/kg, which reaches the international advanced level and has high engineering application value.