A channel state information sending method comprising: sending, by a base station, second signaling to a terminal device, wherein the second signaling comprises sounding reference signal, SRS, information of each of a plurality of subbands, and the SRS information of each subband comprises at least a period of an SRS in the subband; receiving, by the base station in at least one of the plurality of subbands, an SRS of at least one subband from the terminal device; and measuring, by the base station, the SRS of the at least one subband, to obtain channel state information; wherein the at least one subband is the same as the plurality of subbands; the second signaling is physical layer signaling, and the physical layer signaling further comprises a valid time period; and the valid time period is shared by the plurality of subbands, and the valid time period is used to indicate that the terminal device sends the SRS of the at least one subband to the base station within the valid time period; or there are a plurality of valid time periods, each subband corresponds to one of the plurality of valid time periods, and each valid time period is used to indicate that the terminal device sends the SRS to the base station within the valid time period in a subband corresponding to the valid time period; characterized in that the valid time period of the physical layer signaling is one hour after the physical layer signaling is received, wherein the physical layer signaling is used to indicate, to the terminal device, to: stop sending the SRS of the at least one subband to the base station after receiving the physical layer signaling, continue to send the SRS of the at least one subband to the base station after one hour, and determine, based on newly received physical layer signaling after subsequently receiving the physical layer signaling, a state of executing the second signaling. sending, by a base station, second signaling to a terminal device, wherein the second signaling comprises sounding reference signal, SRS, information of each of a plurality of subbands, and the SRS information of each subband comprises at least a period of an SRS in the subband; receiving, by the base station in at least one of the plurality of subbands, an SRS of at least one subband from the terminal device; and measuring, by the base station, the SRS of the at least one subband, to obtain channel state information; wherein the at least one subband is the same as the plurality of subbands; the second signaling is physical layer signaling, and the physical layer signaling further comprises a valid time period; and the valid time period is shared by the plurality of subbands, and the valid time period is used to indicate that the terminal device sends the SRS of the at least one subband to the base station within the valid time period; or there are a plurality of valid time periods, each subband corresponds to one of the plurality of valid time periods, and each valid time period is used to indicate that the terminal device sends the SRS to the base station within the valid time period in a subband corresponding to the valid time period; characterized in that the valid time period of the physical layer signaling is one hour after the physical layer signaling is received, wherein the physical layer signaling is used to indicate, to the terminal device, to: stop sending the SRS of the at least one subband to the base station after receiving the physical layer signaling, continue to send the SRS of the at least one subband to the base station after one hour, and determine, based on newly received physical layer signaling after subsequently receiving the physical layer signaling, a state of executing the second signaling. stop sending the SRS of the at least one subband to the base station after receiving the physical layer signaling, continue to send the SRS of the at least one subband to the base station after one hour, and determine, based on newly received physical layer signaling after subsequently receiving the physical layer signaling, a state of executing the second signaling.