Abstract: As the clock source for secondary devices such as relay protection, integrated automation, and fault recording in substations, the reliability of the clock synchronization device directly affects the safe operation of the substation. In older substations, clock synchronization devices generally use dual clock sources from GPS and BeiDou. However, with the increasing requirements for independent control and security, there is an urgent need to upgrade domestic clock synchronization devices to dual BeiDou clock sources. Traditional full-panel replacement methods have the disadvantages of high renovation costs and long construction periods. This paper proposes a dual BeiDou upgrade method for clock synchronization devices based on panel modification, which can significantly reduce renovation costs and shorten construction time.