Abstract: The China initiative Accelerator Driven System (CiADS) is a significant scientific infrastructure project that was a priority during the 12th Five-Year Plan period in China, which imposes stringent requirements on the reliability of the accelerator beam state and its control system. To support technical validation, the Institute of Modern Physics, Chinese Academy of Sciences, developed the ADS proton superconducting linear accelerator prototype (CAFe). The objective of this study is to enhance the reliability and availability of the beam permit system to meet the higher requirements of CiADS for beam availability and control system reliability. In this study, the IEC 61508 standard is introduced and its relevant concepts and development processes are summarized. In terms of hardware, a redundant design and fault detection mechanisms are adopted to improve the reliability and fault tolerance of the hardware system. In the aspect of software, the appropriate software architectures and security measures are selected, and the application software is implemented with safety attributes through modular design and structured programming. Through the integration of IEC 61508, the system ensures compliance with high reliability and safety requirements throughout its design, development, and operation phases, thereby guaranteeing the availability and reliability of the accelerator facility.