Method and apparatus for determining transport block size

Disclosed in the embodiments of the present application are a method and an apparatus for determining a transport block size (TBS). The method comprises: a terminal device receiving control information sent by a network device, the control information comprising indication information and resource information concerning a data channel; the terminal device determining, according to a first mapping relationship set and the indication information, a modulation mode and an encoding rate, and determining the number of time-frequency resources according to the resource information concerning the data channel; the terminal device determining a TBS according to the modulation mode, the encoding rate and the number of time-frequency resources; and the terminal device decoding, on the basis of the TBS, the data channel borne on the time-frequency resources or the terminal device sending, on the basis of the TBS, the data channel on the time-frequency resources. The embodiments of the present application have the advantage of improving efficiency in determining the TBS, thereby improving the transmission efficiency of the data channel.