This paper presents the design and implementation of a 12kW@2K supercritical helium cryogenic control system for the Shanghai Hard X-ray Free Electron Laser Facility (SHINE). The system provides a stable cryogenic environment for 56 standard 1.3 GHz superconducting modules, meeting the stringent temperature control requirements of the accelerator for high-precision operation of superconducting cavities. A distributed PLC architecture integrated with EPICS is adopted, comprising three refrigerators, four distribution valve boxes, and 39 module subsystems. Redundant network design ensures reliable data transmission. Core functionalities include a four-stage automated cooling process (from 300 K 9
to 2 K), dynamic power compensation, and a safety interlock
mechanism.Experimental results demonstrate that the system maintains the liquid helium bath level within ±1% and pressure within 3100 Pa ± 10 Pa, significantly reducing the quench frequency of the superconducting cavities. Dynamic power compensation adjusts heater power in real time based on a model correlating cavity pressure with heat load, ensuring stability during cryogenic operation. The system has been successfully applied in the commissioning of the injector section, validating its efficiency and safety in providing a cryogenic environment for superconducting accelerators, and serving as a key technical foundation for the SHINE project.