Method for efficiently transmitting channel quality information in mimo system

An efficient CQI(Channel Quality Information) transmission method in an MIMO(Multi Input Multi Output) system is provided to be capable of feeding back more exact channel information to a sending side as minimizing an amount of CQI. The first channel information of more than two pieces of channel information is transmitted. Channel information except the first channel information is transmitted in a type of differential information from the first channel information. The type of the differential information is shown as a type of a particular value within a differential value range determined by considering probability distribution of the differential information.