A method for preparing the iron core of a high-performance high-speed permanent magnet synchronous motor includes selecting materials as follows: adopting high magnetic inductance silicon steel sheetwith magnetic inductance not less than 1.65 T, iron los not more than 2.1 W/Kg, and high-frequency iron loss P1.0/400 not more than 15W/Kg as a stator; The rotor is made of silicon steel sheet with magnetic inductance of 0.5 ~ 1.65 T, yield strength of not less than 400 MPa and tensile strength of not less than 500 MPa; Stamping into sheets; The stamping sheets are laminated into stator core and rotor core of different specifications and models, and matched for use. According to the characteristics of the stator and the rotor of the high-speed permanent magnet synchronous motor, by selecting different silicon steel plates to meet the requirements of service performance, and by reasonably arranging stators and rotors of different specifications on the corresponding silicon steel plates, one-off punching and laminating can be carried out, so as to maximize the use of the selected steel plates, and the comprehensive production cost can be reduced.