A random access resource configuration method and a communications device. The method includes receiving, by a terminal device, index indication information, where the index indication information is used to indicate a first configuration index, determining, by the terminal device based on the first configuration index, first configuration information corresponding to the first configuration index, where the first configuration information is used to indicate a time domain resource for a first group of random access preamble occasions (ROs) or a time domain resource for a second group of ROs, and where the time domain resource for the first group of ROs and the time domain resource for the second group of ROs are located in a first time unit in a random access configuration period.