UHF RFID is becoming the main stream of passive RFID applications. Reader is a key component of a RFID application system. Based on the ARM9 chip S3C2440, the UHF reader ASIC AS3990 and a battery charger 9-channel programmable DC-DC power management chip SMB122, a low-power handheld UHF RFID reader is designed and implemented in this paper. In addition to long enough read range, the power consumption is also important for a handheld RFID reader. A low-power control program is analysed and designed in detail in this paper.