A method for reporting Channel State Information, CSI, characterized by comprising: determining, by a terminal device, second information in a second CSI part according to first information in a first CSI part, wherein the second information comprises at least one of: a Precoding Matrix Indicator, PMI, or a Channel Quality Indicator, CQI; and reporting, by the terminal device, the CSI, wherein the CSI comprises the first CSI part and the second CSI part, wherein determining, by the terminal device, the second information in the second CSI part according to the first information in the first CSI part comprises: determining, by the terminal device, that the second CSI part comprises one PMI in a case that a value of the first information is a first value, wherein all information in the CSI is obtained by performing measurement based on a single measurement resource; and determining, by the terminal device, that the second CSI part comprises two PMIs and k CQI in a case that the value of the first information is a second value, wherein a value of k is 0 or 1, and the two PMIs are obtained by performing measurement based on different measurement resources; and wherein CQI comprised in the first CSI part is obtained by performing calculation based on the two PMIs in a case that the value of k is 0; wherein one measurement resource comprises at least one of: one Channel Measurement Resource, CMR, or one Interference Measurement Resource, IMR. determining, by a terminal device, second information in a second CSI part according to first information in a first CSI part, wherein the second information comprises at least one of: a Precoding Matrix Indicator, PMI, or a Channel Quality Indicator, CQI; and reporting, by the terminal device, the CSI, wherein the CSI comprises the first CSI part and the second CSI part, wherein determining, by the terminal device, the second information in the second CSI part according to the first information in the first CSI part comprises: determining, by the terminal device, that the second CSI part comprises one PMI in a case that a value of the first information is a first value, wherein all information in the CSI is obtained by performing measurement based on a single measurement resource; and determining, by the terminal device, that the second CSI part comprises two PMIs and k CQI in a case that the value of the first information is a second value, wherein a value of k is 0 or 1, and the two PMIs are obtained by performing measurement based on different measurement resources; and wherein CQI comprised in the first CSI part is obtained by performing calculation based on the two PMIs in a case that the value of k is 0; wherein one measurement resource comprises at least one of: one Channel Measurement Resource, CMR, or one Interference Measurement Resource, IMR. determining, by the terminal device, that the second CSI part comprises one PMI in a case that a value of the first information is a first value, wherein all information in the CSI is obtained by performing measurement based on a single measurement resource; and determining, by the terminal device, that the second CSI part comprises two PMIs and k CQI in a case that the value of the first information is a second value, wherein a value of k is 0 or 1, and the two PMIs are obtained by performing measurement based on different measurement resources; and wherein CQI comprised in the first CSI part is obtained by performing calculation based on the two PMIs in a case that the value of k is 0; wherein one measurement resource comprises at least one of: one Channel Measurement Resource, CMR, or one Interference Measurement Resource, IMR.