A channel quality information calculation method, wherein the method comprises: receiving, by a terminal, a downlink configuration instruction sent by an access network device; performing, by the terminal, measurement on a reference signal resource indicated by the downlink configuration instruction, to obtain first channel quality information, and sending the first channel quality information to the access network device, wherein the first channel quality information is used to feedback received signal information obtained through measurement on the reference signal resource; and sending, by the terminal, a sounding reference signal, SRS, to the access network device, wherein the first channel quality information and the SRS are used to calculate second channel quality information and wherein a signal-to-noise ratio, SNR, of a downlink channel is determined as the second channel quality information by: obtaining, by the access network device, received signal information of the terminal from the first channel quality information; performing, by the access network device, calculation based on the SRS, to obtain channel estimation information of the downlink channel of the terminal; performing, by the access network device, calculation based on the received signal information and the channel estimation information of the downlink channel, to obtain interference information; and performing, by the access network device calculation based on the interference information and the channel estimation information of the downlink channel, to obtain the SNR and determining the SNR as the second channel quality information. receiving, by a terminal, a downlink configuration instruction sent by an access network device; performing, by the terminal, measurement on a reference signal resource indicated by the downlink configuration instruction, to obtain first channel quality information, and sending the first channel quality information to the access network device, wherein the first channel quality information is used to feedback received signal information obtained through measurement on the reference signal resource; and sending, by the terminal, a sounding reference signal, SRS, to the access network device, wherein the first channel quality information and the SRS are used to calculate second channel quality information and wherein a signal-to-noise ratio, SNR, of a downlink channel is determined as the second channel quality information by: obtaining, by the access network device, received signal information of the terminal from the first channel quality information; performing, by the access network device, calculation based on the SRS, to obtain channel estimation information of the downlink channel of the terminal; performing, by the access network device, calculation based on the received signal information and the channel estimation information of the downlink channel, to obtain interference information; and performing, by the access network device calculation based on the interference information and the channel estimation information of the downlink channel, to obtain the SNR and determining the SNR as the second channel quality information. obtaining, by the access network device, received signal information of the terminal from the first channel quality information; performing, by the access network device, calculation based on the SRS, to obtain channel estimation information of the downlink channel of the terminal; performing, by the access network device, calculation based on the received signal information and the channel estimation information of the downlink channel, to obtain interference information; and performing, by the access network device calculation based on the interference information and the channel estimation information of the downlink channel, to obtain the SNR and determining the SNR as the second channel quality information.