Provided are a vehicle-to-everything synchronization method and device. The method is used for a first terminal, wherein the first terminal can simultaneously support first-type vehicle-to-everything direct communication and second-type vehicle-to-everything direct communication. The method includes: receiving at least one first synchronization signal, wherein the at least one first synchronization signal is a synchronization signal for the first-type vehicle-to-everything direct communication and/or the second-type vehicle-to-everything direct communication; determining a synchronization reference signal for the second-type vehicle-to-everything direct communication according to the first synchronization signal; and performing the second-type vehicle-to-everything direct communication according to the synchronization reference signal. Therefore, according to the present disclosure, a synchronization signal of one type of network can be used to provide a synchronization reference signal for another type of network communication, and the synchronization efficiency of vehicle-to-everything can also be realized.