This application provides an indication method and a communications apparatus. The method includes: receiving, by a terminal device, configuration information sent by a network device, where the configuration information includes at least two of a subcarrier configuration parameter, a time parameter of a first period, and a total quantity of slots included in the first period; and determining, by the terminal device based on the configuration information, information about a second period within which the terminal device performs data transmission by using a bandwidth part BWP. According to the indication method provided in this application, the network device may notify the terminal device of a plurality of SCSs supported by a cell and period information corresponding to the SCSs. After receiving the configuration information, the terminal device may determine, based on a subcarrier configuration parameter that is used by the bandwidth part BWP used for transmitting data and that is configured for the terminal device by the network device, information about a period within which data transmission is performed by using the BWP, so that the terminal device transmits data by using the cell. In this way, data transmission efficiency is improved and user experience is improved.