A low phase noise CMOS LC Voltage Controlled Oscillator for 860~960MHz UHF RFID (Radio Frequency Identification) reader is designed.The quadrature output differential signal is achieved through SCL (Source-Coupled Logic) frequency divider by two.The circuit is implemented with the SMIC 0.18μm CMOS technology and the simulator of Cadence SpectreRF.The simulation results show the frequency range from 1620~2020MHz before frequency divider and phase noise of-127.5dBc/Hz@1MHz offset at oscillation frequency of 1.8GHz.VCO has the frequency rang from 810~1010MHz after frequency divider by two and the phase noise of-133.5dBc/Hz@1MHz offset at the frequency of 900MHz.