A method for improving energy efficiency performance of a reader is disclosed in the present document. The method includes: initializing and adjusting operation parameters, and acquiring the current number of frame timeslots; updating a frame timeslot status, and determining that a power level is not required to be increased according to the updated frame timeslot status; and estimating the number of labels according to the current number of frame timeslots, and acquiring an optimum Q value according to the number of labels. A device for improving energy efficiency performance of a reader is also disclosed in the present document. With the method and device of the present document, throughput of a Radio Frequency Identification (RFID) system is maximized, thereby reducing energy consumption of the system and extending usage time of the system; and while the energy consumption is reduced, a rate at which the reader reads the labels is guaranteed.