An information transmission method performed by a network device, the method comprising: • generating first information (S 301); and • sending the first information to a terminal device (S 302), wherein the first information is used to instruct the terminal device to detect at least one group common physical downlink control channel, PDCCH, on N component carriers, CCs, N is a positive integer and is less than or equal to M, M is a quantity of CCs configured for the terminal device, and M is a positive integer, wherein the group common PDCCH is used to indicate group user equipment, UE, common information, of the M CCs, configured for the terminal device, wherein the group UE common information of the M CCs is used to indicate information common to a UE group, the UE group containing the terminal device, and the group UE common information of the M CCs includes a plurality of fields, wherein different fields among the plurality of fields contain group UE common information of different CCs among the M CCs, wherein the first information comprises: ∘ in a first alternative, for each CC among the M CCs, a correspondence between an index value of the CC, an index value of a CC among the N CCs and a different field among the plurality of field; or ∘ in a second alternative instead of the first alternative, for each CC among the M CCs, a correspondence between the index value of the CC, the index value of the CC among the N CCs, a different field among the plurality of fields, and identification information used for scrambling the group UE common information of the M CCs, • in the first alternative: ∘ sending the group UE common information of the M CCs to the terminal device on the at least one group common PDCCH, in the second alternative: ∘ scrambling the group UE common information of the M CCs by using identification information of a CC group in which the N CCs are located, or scrambling the group UE common information of the M CCs by using identification information of the terminal device group in which the terminal device is located, or scrambling the group common PDCCH by using identification information of the terminal device, and sending the scrambled group UE common information of the M CCs on the at least one group common PDCCH to the terminal device. • generating first information (S 301); and • sending the first information to a terminal device (S 302), wherein the first information is used to instruct the terminal device to detect at least one group common physical downlink control channel, PDCCH, on N component carriers, CCs, N is a positive integer and is less than or equal to M, M is a quantity of CCs configured for the terminal device, and M is a positive integer, wherein the group common PDCCH is used to indicate group user equipment, UE, common information, of the M CCs, configured for the terminal device, wherein the group UE common information of the M CCs is used to indicate information common to a UE group, the UE group containing the terminal device, and the group UE common information of the M CCs includes a plurality of fields, wherein different fields among the plurality of fields contain group UE common information of different CCs among the M CCs, wherein the first information comprises: ∘ in a first alternative, for each CC among the M CCs, a correspondence between an index value of the CC, an index value of a CC among the N CCs and a different field among the plurality of field; or ∘ in a second alternative instead of the first alternative, for each CC among the M CCs, a correspondence between the index value of the CC, the index value of the CC among the N CCs, a different field among the plurality of fields, and identification information used for scrambling the group UE common information of the M CCs, ∘ in a first alternative, for each CC among the M CCs, a correspondence between an index value of the CC, an index value of a CC among the N CCs and a different field among the plurality of field; or ∘ in a second alternative instead of the first alternative, for each CC among the M CCs, a correspondence between the index value of the CC, the index value of the CC among the N CCs, a different field among the plurality of fields, and identification information used for scrambling the group UE common information of the M CCs, • in the first alternative: ∘ sending the group UE common information of the M CCs to the terminal device on the at least one group common PDCCH, in the second alternative: ∘ scrambling the group UE common information of the M CCs by using identification information of a CC group in which the N CCs are located, or scrambling the group UE common information of the M CCs by using identification information of the terminal device group in which the terminal device is located, or scrambling the group common PDCCH by using identification information of the terminal device, and sending the scrambled group UE common information of the M CCs on the at least one group common PDCCH to the terminal device. ∘ sending the group UE common information of the M CCs to the terminal device on the at least one group common PDCCH, in the second alternative: ∘ scrambling the group UE common information of the M CCs by using identification information of a CC group in which the N CCs are located, or scrambling the group UE common information of the M CCs by using identification information of the terminal device group in which the terminal device is located, or scrambling the group common PDCCH by using identification information of the terminal device, and sending the scrambled group UE common information of the M CCs on the at least one group common PDCCH to the terminal device.