A robust passive UHF RFID backscatter systemenhanced with spread spectrum technique is presented in thispaper. Due to the weak signal energy of the backscatter chain,traditional RFID backscatter communication is easily affected bythe noises, interferences, and interceptions from theenvironment. To solve the problem, spread spectrum techniqueis introduced into the backscatter link of RFID system.Simulated results show that this approach largely reduces the BitError Rate and improves the system’s reliability and security.For hardware realization, spectrum spreading operation isimplemented in a RFID tag baseband processor, which is finallyapplied into a complete RFID tag and fabricated using 0.18um1P6M CMOS technology. Furthermore, de-spreading operationincluding the PN acquisition is integrated into a FPGAimplementation of RFID reader. Thus, a complete robust RFIDbackscatter system enhanced with spread spectrum technique isconstructed.