In order to overcome the disadvantages of electric propulsion motor of contra-rotating propellers, designed a new structural permanent disc contra-rotating motor of single stator and double rotor. Described the motor’s basic structure, operating principle and magnetic circuit characteristics, analyzed the coupling problem of contra-rotating magnetic field in the motor, and introduced the equivalent magnetic circuit model. In Cartesian coordinates, provided the magnetic flux density formula of rotor magnetic pole surface and analyzed the air gap magnetic field and the air gap flux density of the average radius by means of the finite element method. Made a disc contra-rotating motor prototype, and built an experimental platform to test the three-phase induction electromotive force of the motor. The test results show that due to the asymmetric length end of stator winding, the unbalanced three-phase induction electromotive force is found.