This paper presents a low phase noise of the complementary cross-coupled voltage-controlled oscillator, which oscillates at a range of 7.42~8.52 GHz. This VCO utilizes switching capacitor modules in which four channels are able to be selected. Moreover, We makes good use of filtering technique for reduction 1/f noise, and MOS varactors are used as fine tuning. The fully integrated VCO provides excellent performance with high FOM -193 dBc/Hz. The bandwidth of frequency is 1.1 GHz and the tuning range is 13.8%. The power dissipation of the core circuit is 8.28 mW under 1.8 V supply and phase noises all are smaller than -124.3 dBc/Hz at 1 MHz offset. This VCO was made by TSMC 0.18 mum 1P6M CMOS standard process and the chip area is 0.75times 0.69 (mm2).