The present application discloses a signal transmission method and a device, for achieving PRS transmission supporting different bandwidths and numerology. The embodiment of the present application provides a signal transmission method, the method includes: receiving and measuring a cell-level cell-specific first positioning reference signal PRS in a cell public measurement window, to obtain a first positioning measurement value, and applying to the network side for a terminal-level UE-specific second PRS resource in a non-cell public measurement window based on the first positioning measurement value; receiving and measuring the UE-specific second PRS in the non-cell public measurement window, to obtain a second positioning measurement value; determining and reporting a third positioning measurement value based on the first positioning measurement value and the second positioning measurement value.