In order to meet the demand of research requirements of the coaxial rigid rotor high-speed helicopter in China, the automatic trim technology of coaxial rigid rotor test is studied. Based on the existing test platform, combined with the trim principle of the coaxial rigid rotor, and referring to the automatic trim technology of the single rotor, the automatic trim technology of the coaxial rigid rotor test based on fuzzy control is proposed. It is tested and verified in the experiment and reached the practical stage.