A DFE circuit for use in a semiconductor memory device and an initializing method thereof. In the method of initializing a DFE circuit used in a semiconductor memory device having a discontinuous data transmission, the DFE circuit may be used for changing a sampling reference level in response to a level of previous data and sampling transmission data. The method includes terminating a data channel having a transmission of the transmission data at a predefined termination level, and controlling a sampling start time point of the transmission data as a time point preceding a transmission time point of the transmission data by a predefined time. Further, an initialization may be performed of the previous data on the basis of initialization data obtained through a pre-sampling of the data channel at a sampling start time point of the transmission data, thereby obtaining an initialization of the DFE circuit and compensating for a feedback delay.