A method for determining a sidelink type, a terminal device, and a network device are provided. The method comprises: receiving downlink control information (DCI) sent by a network device; determining, on the basis of the DCI, a first type of sidelink or a second type of sidelink as a target sidelink according to a preset rule, the first type of sidelink being different from the second type of sidelink in configuration parameters; and using the target sidelink to perform data transmission of the sidelink.