A Quad-Data Rate (QDR) controller and an implementation method thereof are disclosed in the present invention. The controller includes: an arbiter, a control state machine, a read data sampling clock generating module, a read data path module and a read data path calibrating module. The arbiter arbitrates commands and data according to the state of the control state machine; the read data sampling clock generating module generates read data sampling clocks with the same source and same frequency and different phases; the read data path calibrating module 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”; the read data path module 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. The present invention has a shorter delay and does not need any programmable delay element, and is easy to implement.