Abstract: Linear generator is the core component of Stirling thermal generator set. In order to improve the disadvantages of existing solar energy dish Stirling generator, such as low power density and low utilization of ferromagnetic materials, the design scheme of composite permanent magnet linear generator was proposed. Due to the effect of magnetic field modulation, the induced electromotive force with relatively high amplitude and frequency can still be obtained at the stator side when the motor moves at low speed. The whole motor adopts flat topology structure, and the outer stator and magnetic field modulation variable speed module were integrated in parallel and coaxial, which could reduce the machining difficulty. The Halbach magnetization method was adopted in both high speed and low speed speed mover permanent magnets to form magnetic focusing loops, which could improve the fundamental amplitude of EMF and reduce the harmonic content. At the same time, the damping winding was introduced into the high-speed mover side to effectively suppress the mechanical oscillation caused by the thrust fluctuation of the Stirling machine. By establishing the equivalent magnetic circuit model of the motor, the magnetomotive force and permeance function of the motor at different displacement points were analyzed, which provided the basis for parameter optimization design. According to the design scheme, the prototype was manufactured, and the experimental results were basically consistent with the calculation results, which verified the correctness of the design scheme.