Provided are a data transmission method, a terminal device and a network device. The method comprises: a terminal device acquires a plurality of sounding reference signal resource indications (SRIs) from downlink control information (DCI) for scheduling uplink data, each SRI among the plurality of SRIs corresponding to at least one power control parameter; the terminal device determines a target SRI among the plurality of SRIs; the terminal device determines a power control parameter of the uplink data according to the at least one power control parameter corresponding to the target SRI; and the terminal device determines the transmit power of the uplink data according to the power control parameter of the uplink data. According to the embodiments of the present invention, the terminal device may determine a target SRI among a plurality of SRIs and accurately determine the transmit power of uplink data according to at least one power control parameter corresponding to the target SR, thereby improving data transmission efficiency.