Provided are a synchronization signal transmission method, a transmitting end device and a receiving end device. A frequency domain candidate position (also called SS raster) of a synchronization signal on an unlicensed frequency band is designed, the complexity of initial cell search is reduced, and the impact, on the other channels in a subband, of the position of the initial access of a cell in the unlicensed frequency band to a synchronization signal block in the subband is also reduced. The method comprises: a transmitting end device sending a synchronization signal block at a first frequency domain position, wherein the first frequency domain position is located at a frequency domain candidate position of a synchronization signal, and each 20 MHz subband comprises at least one of the synchronization signal frequency domain candidate positions.