The implementations of the present disclosure relate to a control information transmission method, a terminal device and a network device. The method comprises: a terminal device receiving downlink control information (DCI) sent by a network device, wherein the DCI comprises at least one information block, and a first information block of the at least one information block comprises control information of a first cell; and the first information block comprises at least one of the following: an identifier of the first cell, slot format indication (SFI) information, frequency domain resource indication information, frequency domain resource, end position information of the COT, physical random access channel (PRACH) resource indication information, and position indication information of a synchronization signal block (SSB).