A high frequency complex Gm-C filter was proposed by using 0.18 μm CMOS RF process. The filter has 20 MHz bandwidth and is centered at 46 MHz, while the pass-band flatness is less than 0.36 dB. The image band rejection is higher than 98 dB, and the out-band rejection is higher than 28 dB. The complete filter consumes less than 7.9 mA with 1.8 V supply voltage. An integrator with digital circuits based frequency tuning circuit was used to realize the automatic tuning of both center frequency and band-width. On the completion of the tuning, the circuit will automatically shut down. The 'zero power' is particularly suitable for low power applications. Simulation results show that the tuning error is less than ±1.5%.