The invention belongs to the technical field of wireless communication, and in particular discloses a location method and a device of wireless radio frequency identification system; wherein, a carrier wave is generated from a radio frequency identification reader of the system and modulated by a pseudorandom sequence; the modulation depth of the modulated carrier wave is small and has little influence on the normal work of label; the detection label of the reader returns modulation signals and restores pseudorandom sequence synchronously; the restored and sent pseudorandom sequences are interrelated by the reader to obtain the signal of TOA and the distance between the label and the reader is calculated; one or a plurality of reference label verification can remove signal treatment delay and system error and improve location precision; multi readers can obtain multi distances; if the readers are taken as centers of circles and correspondent distances are taken as radii, then the pointof intersection of the circles is the estimation location of the detected labels. The invention has high location precision and is affected little by the environment.