The invention provides a road side unit wireless synchronization method, road side units and a system. The road side unit wireless synchronization method includes the following steps that: a first road side unit (RSU) sends a first synchronization signal to a second RSU and simultaneously generates a second synchronization signal, wherein frequency points arranged by the first RSU and the second RSU are the same, the first RSU is a master mode device, and the second RSU is a slave mode device; and the first RSU sends dedicated short-range communication (DSRC) data after acquiring the second synchronization signal. According to the method provided by the invention, multiple RSUs in the same group are subjected to data synchronization in a wireless manner, the process of carrying out threading between lanes is not required, the operation is more convenient and faster, and the cost can be reduced.