A measurement method, comprising: step A: sending, by a network device, a channel state information-reference signal, CSI-RS, measurement beam to a terminal device, wherein the CSI-RS measurement beam is obtained by the network device by weighting a CSI-RS by using a beamforming weight, and the beamforming weight is used to perform beamforming on the CSI-RS; step B: receiving, by the network device, a rank indicator and a channel quality indicator that are determined by the terminal device based on the CSI-RS measurement beam; and weighting and transmitting, by the network device, a downlink channel based on the rank indicator and the channel quality indicator; wherein before step A, the method further comprises: receiving, by the network device, an uplink sounding reference signal, SRS, sent by the terminal device; and determining, by the network device, the beamforming weight based on the SRS comprising determining, by the network device, an uplink channel matrix based on the SRS; and decomposing, by the network device, the uplink channel matrix to obtain the beamforming weight; wherein between step A and step B, the method further comprises: sending, by the network device, indication information to the terminal device, wherein the indication information is used to indicate a quantity of CSI-RS ports to the terminal device; characterized in that before the sending, by the network device, indication information to the terminal device, the method further comprises: determining, by the network device, the quantity of CSI-RS ports based on a distance between the network device and the terminal device. step A: sending, by a network device, a channel state information-reference signal, CSI-RS, measurement beam to a terminal device, wherein the CSI-RS measurement beam is obtained by the network device by weighting a CSI-RS by using a beamforming weight, and the beamforming weight is used to perform beamforming on the CSI-RS; step B: receiving, by the network device, a rank indicator and a channel quality indicator that are determined by the terminal device based on the CSI-RS measurement beam; and weighting and transmitting, by the network device, a downlink channel based on the rank indicator and the channel quality indicator; wherein before step A, the method further comprises: receiving, by the network device, an uplink sounding reference signal, SRS, sent by the terminal device; and determining, by the network device, the beamforming weight based on the SRS comprising determining, by the network device, an uplink channel matrix based on the SRS; and decomposing, by the network device, the uplink channel matrix to obtain the beamforming weight; wherein between step A and step B, the method further comprises: sending, by the network device, indication information to the terminal device, wherein the indication information is used to indicate a quantity of CSI-RS ports to the terminal device; characterized in that before the sending, by the network device, indication information to the terminal device, the method further comprises: determining, by the network device, the quantity of CSI-RS ports based on a distance between the network device and the terminal device. receiving, by the network device, a rank indicator and a channel quality indicator that are determined by the terminal device based on the CSI-RS measurement beam; and weighting and transmitting, by the network device, a downlink channel based on the rank indicator and the channel quality indicator; wherein before step A, the method further comprises: receiving, by the network device, an uplink sounding reference signal, SRS, sent by the terminal device; and determining, by the network device, the beamforming weight based on the SRS comprising determining, by the network device, an uplink channel matrix based on the SRS; and decomposing, by the network device, the uplink channel matrix to obtain the beamforming weight; wherein between step A and step B, the method further comprises: sending, by the network device, indication information to the terminal device, wherein the indication information is used to indicate a quantity of CSI-RS ports to the terminal device; characterized in that before the sending, by the network device, indication information to the terminal device, the method further comprises: determining, by the network device, the quantity of CSI-RS ports based on a distance between the network device and the terminal device. sending, by the network device, indication information to the terminal device, wherein the indication information is used to indicate a quantity of CSI-RS ports to the terminal device; characterized in that before the sending, by the network device, indication information to the terminal device, the method further comprises: determining, by the network device, the quantity of CSI-RS ports based on a distance between the network device and the terminal device.