A Quad-Data Rate (QDR) controller and an implementation method thereof are disclosed in the present invention. The controller includes: an arbiter, used to arbitrates commands and data according to the state of the control state machine; a read data sampling clock generating module, used to generate read data sampling clocks with the same source and same frequency and different phases; a read data path calibrating module, used to determines, among the generated read data sampling clocks, sampling clocks of positive edge data and negative edge data for the read data path module to read data by reading training words when the control state machine is in “read data path calibrating state”; a read data path module, used to synchronizes the positive edge read data and negative edge data in a non-system clock domain to the system clock domain according to the determined sampling clocks.