Provided are a method for determining a spatial domain parameter, a terminal, and a network-side device. The method for determining a spatial domain parameter in the embodiments of this application includes: determining, by a terminal based on whether uplink transmission and downlink reception are present on a first time domain unit, a spatial domain parameter used for uplink transmission or downlink reception, where the first time domain unit is an SBFD time domain unit; and performing, by the terminal, uplink transmission or downlink reception using the spatial domain parameter.