Time synchronization technology is pivotal in ensuring the harmonious and precise operation of distributed control systems. It furnishes a unified temporal reference for the synchronized efforts of each node, thereby offering crucial assurances for the real-time precision and collaborative functionality of the control system. Time synchronization technology ensures that the platform can achieve comprehensive and efficient real-time status monitoring of nuclear power plants. Furthermore, high-precision time synchronization enhances the event resolution capabilities of digital instrument and control systems. More importantly, the time system holds significant engineering application importance as it provides a temporal foundation for event occurrence, data acquisition, and accident analysis functions within the digital instrument and control system. Based on the above, this paper proposed a comprehensive time synchronization technology for the non-safety nuclear instrumentation I&C distributed control system (DCS) based on the precise timing protocol. We designed and implemented full-featured support for the master–slave timing function of the main data processing controller, encompassing hardware design, system drivers, application software, and other aspects, ensuring the core data processing unit of the Level-One control station, which can effectively support time synchronization technology and meet stringent time accuracy requirements. Additionally, by analyzing various PTP timing methods within the prceise timing protocol, and taking into account network topology, system performance requirements, and other factors, we proposed a system-level time synchronization deployment strategy and recommendations for system nodes, including the DPUs, clock server, and network management switches. This approach holds high practical application value and meets the demands of DCS systems in nuclear power plants.