Abstract: This application discloses a clock synchronization system, including a quantum control processor (QCP) and N digital/analog mutual conversion devices, each digital/analog mutual conversion device including a frequency conversion module and a signal synchronization module that includes a D flip-flop (DFF). The QCP generates a global synchronization signal and reference clock signals; and transmits the global synchronization signal and a reference clock signal to the frequency conversion module and transmits the global synchronization signal to the signal synchronization module of each conversion device. The frequency conversion module performs frequency conversion processing on the reference clock signal to obtain a target clock signal, and generates a signal synchronization instruction according to the global synchronization signal; and transmits the signal synchronization instruction and the target clock signal to the signal synchronization module.