An information sending method performed by a terminal device or a chip in the terminal device, comprising: sending first information to a network device, wherein the first information indicates that the terminal device is a first-type terminal device, wherein the first-type terminal device is a reduced-capability, REDCAP, terminal device, a capability parameter corresponding to the first-type terminal device comprises a first capability set, the first capability set comprises a channel bandwidth supported by the terminal device, a quantity of transmit antennas of the terminal device and a quantity of receive antennas of the terminal device, the channel bandwidth of the terminal device is less than 100 megahertz, and the quantity of transmit antennas of the terminal device is less than 4, the quantity of receive antennas of the terminal device is less than 4, and the first information is carried in a preamble, a message 3, Msg3, or a message A, MsgA; sending second information to the network device, wherein the second information indicates that the capability parameter corresponding to the first-type terminal device further comprises at least one of a second capability set, a fourth capability set, a fifth capability set, or a sixth capability set, and the second information is sent in a connected state, wherein the second capability set is used to represent a power saving capability of the terminal device, the fourth capability set is used to represent a short-latency processing capability of the terminal device; the fifth capability set is used to represent a small data transmission capability of the terminal device, the sixth capability set is used to represent a transmission reliability capability of the terminal device. sending first information to a network device, wherein the first information indicates that the terminal device is a first-type terminal device, wherein the first-type terminal device is a reduced-capability, REDCAP, terminal device, a capability parameter corresponding to the first-type terminal device comprises a first capability set, the first capability set comprises a channel bandwidth supported by the terminal device, a quantity of transmit antennas of the terminal device and a quantity of receive antennas of the terminal device, the channel bandwidth of the terminal device is less than 100 megahertz, and the quantity of transmit antennas of the terminal device is less than 4, the quantity of receive antennas of the terminal device is less than 4, and the first information is carried in a preamble, a message 3, Msg3, or a message A, MsgA; sending second information to the network device, wherein the second information indicates that the capability parameter corresponding to the first-type terminal device further comprises at least one of a second capability set, a fourth capability set, a fifth capability set, or a sixth capability set, and the second information is sent in a connected state, wherein the second capability set is used to represent a power saving capability of the terminal device, the fourth capability set is used to represent a short-latency processing capability of the terminal device; the fifth capability set is used to represent a small data transmission capability of the terminal device, the sixth capability set is used to represent a transmission reliability capability of the terminal device.