A method of interpolating channel quality in a wireless communication system, the wireless communication system including a node B and a user equipment, the user equipment periodically reporting the channel quality to the node B, the method including the steps of: estimating, by node B, the channel quality of the current period based on the channel quality of the preceding period reported by the user equipment; after obtaining the channel quality of the current period reported by the user equipment, computing, by node B, the difference between the estimated channel quality of the current period and the channel quality of the current period reported by the user equipment; and obtaining, by node B, a confidence parameter according to the difference, and interpolating the channel quality reported by the user equipment based on the confidence parameter. Node B can acquire reliable downlink channel quality information in real time, and thus schedule the users within the cell more reasonably, select the data transport format and control the power more accurately. Thus, the quality of service of the users and the utilization efficiency of the system resources are improved.