A communication device of reporting channel information comprises a storage unit for storing instructions and a processing means coupled to the storage unit. The processing means is configured to execute the instructions stored in the storage unit. The instructions comprise receiving a plurality of beamformed reference signals transmitted by a network via a plurality of beams, respectively; obtaining a plurality of channel quality indicators (CQIs) of the plurality of beams according to the plurality of beamformed reference signals; and transmitting a bitmap indicating whether the plurality of CQIs are greater than a threshold to the network.