A coding scheme determining method and apparatus are provided. In various embodiments, a base station device sends, to a terminal device, higher layer control signaling, physical layer control signaling, or a synchronization signal that carries coding scheme indication information. In some embodiments, a terminal device sends, to a base station device, a capability information report message that carries coding scheme indication information, so that the base station device or the terminal device can clearly and flexibly indicate a coding scheme. At least one information block size IBS greater than or equal to a preset first specified value X is determined, and an IBS is selected from the at least one IBS to code an information block of bits or a code block of the information block of bits. X and a coding scheme are determined by a scenario, information type, and/or service type.