This paper presents a 40 nm CMOS V-band voltage-controlled oscillator (VCO). With using on-chip body bias voltage control technique, the phase noise and stability of the output signal are improved. The design was fabricated by RF Mixed-signal CMOS process with die size 0.078 mm2. Based on the silicon results, the proposed V-band VCO can achieve the phase noise of-86 dBc/Hz at 1 MHz offset. The VCO draws 17.8 mA current from a 1.2 V supply. Compared with the traditional structure VCO of the same batch, the measured FOM is optimized from-165.4 dB to-169 dB, meanwhile the output signal power offset is reduced by 1.8 dBm.