Embodiments of the present application provide a control channel transmission method and apparatus, and a storage medium. A network device determines a first search space set within a COT of a fixed frame period, transmits a first PDCCH in the first search space when it is determined that a resource in the COT is available, and does not transmit a downlink channel or a downlink signal in the COT when it is determined that a resource in the COT is unavailable, where the first PDCCH is used to transmit slot structure indication information, and the slot structure indication information is used to determine a slot structure of the COT. Correspondingly, a terminal device, after determining a first search space set within a COT of a fixed frame period, monitors a first PDCCH according to the first search space set.