Embodiments of this application provide a parameter transmission method and an apparatus, and relate to the field of wireless communication technologies. In the method, the terminal device may receive first information. The first information may include a time parameter. The time parameter may be used to determine a timing offset. The timing offset includes a second timing offset, and the second timing offset indicates a delay of activation of configuration information. The terminal device determines a delay start duration of a random access response (RAR) window based on the second timing offset.