The invention provides a feedback method of channel state information (CSI), a resource allocation method, a terminal, a base station and a device. The feedback method comprises the following steps: measuring a target downlink channel, determining a target CSI of the target downlink channel; decomposing the target CSI into a first CSI and a second CSI, wherein the first CSI comprises a target RI (rank indication), a first PMI (precoding matrix indication) formed by the information required by a precoding matrix for constructing the RI to be equal to 1 in the target PMI, and a first CQI (channel quality indication) computed according to the first PMI; receiving a first indication signaling, feeding back the first CSI on a first uplink channel resource allocated by the base station; and/or receiving a second indication signaling, and feeding back the second CSI on a second uplink channel resource allocated by the base station. Through the feedback method provided by the embodiment of theinvention, the precision of the CSI feedback can be guaranteed, and the effective utilization of the uplink channel resource can be guaranteed.