Abstract: Superconducting synchrocyclotrons offer compact structure and low cost, making them highly suitable for proton therapy systems. This paper presents a preliminary design of a 230 MeV superconducting synchrocyclotron for proton therapy, investigating its main magnet design, transverse and longitudinal dynamics, and regenerator extraction system design. The accelerator features a magnet radius of 1.1 m, pole radius of 0.53 m, and maximum magnetic field of 5.71 T. Dynamic calculations confirm that the magnetic field distribution ensures stable beam transmission. Longitudinal analysis shows the RF frequency varies from 85.6 to 60.5 MHz, with a phase acceptance of 90° achieved at a synchronous phase of 30°. Numerical simulations optimize the regenerator structural parameters, and beam extraction dynamics are analyzed computationally. Results demonstrate that with the regenerator, the reference particle maintains vertical stability even when its radial turn separation exceeds 1.5 cm at the extraction radius. This study provides valuable references for the design of superconducting synchrocyclotrons.