A method for determining a modulation and coding scheme is disclosed. The method is performed by a network device. The method includes: determining a quantity K of terminal devices that reuse a first time-frequency resource in a first time period to receive downlink data from the network device, where K≥2; obtaining a channel quality indicator (CQI), where the CQI is determined according to a signal to interference plus noise ratio (SINR) of a channel and the quantity K of the terminal devices, where the channel is a channel based on the first time-frequency resource, and the channel is used to transmit downlink data between a first terminal device and the network device in the first time period; and determining a Modulation and Coding scheme (MCS) of the first terminal device according to the CQI.