An apparatus for reporting downlink channel quality in a high-speed packet communication system. A channel analyzer measures downlink channel quality from a received reference channel signal. A controller determines whether a current TTI (Transmission Time Interval) is a TTI corresponding to a multiple of a first TTI or a TTI corresponding to a multiple of a second TTI. If the current TTI is a TTI corresponding to a multiple of the first TTI, the controller determines CQ (Channel Quality) refreshment information for a downlink channel received from the Node B based on the measured downlink channel quality, and if the current TTI is a TTI corresponding to a multiple of the second TTI, the controller determines CQ refinement information for the downlink channel based on the measured downlink channel quality. A CQ information transmitter generates CQ refreshment information or CQ refinement information under the control of the controller, and transmits the generated CQ refreshment information or CQ refinement information over an uplink.