The invention provides a channel state information reporting method, a base station and UE. The base station sends allocation information comprising characteristic parameters of a small data package to the UE, so that the UE measures objects indicated in the allocation information and returns a measurement result to the base station. Thus, the current service situation of the UE can be reflected and the base station uses the measurement result as the input. According to the corresponding relation between the measurement result of the characteristic parameters of the small data package of the projects indicated by the preset allocation information measured and reported and CSI reported allocation information, channel state information reported allocation information is determined and sent to the UE. The UE carries out channel state information reporting according to the channel state information reported allocation information. Thus, according to the current service situation of the UE, the channel state information reporting is performed. According to the channel state information reporting method, the base station and the UE, power consumption of the UE can be reduced.