This paper presents a detailed technical overview of the femtosecond precision timing and synchronization systems implemented at the Shanghai High repetition rate XFEL and Extreme light facility (SHINE). These systems are designed to deliver stabilized optical references to multiple receiver clients, ensuring high precision synchronization between optical master oscillator and optical/RF subsystems. The core components include a optical master oscillator, a fiber length stabilizer, and a laser-to-laser synchronization module that achieves femtosecond-level accuracy. Our discussion extends to the various subsystems that comprise the synchronization infrastructure, including the optical master oscillator (OMO), fiber length stabilizer, and advanced phase detection techniques. Finally, we highlight ongoing research and development efforts aimed at enhancing the functionality and efficiency of these systems, thereby contributing to the advancement of XFEL technology and its applications in scientific research.