In order to suppress interferences and improve the linearity of circuits,a SAW-less RF front-end system is designed by using a 0.13 μm RF CMOS process.This design adopts a novel variable-gain low-noise transconductance amplifier with a loop eliminating interferences,a 25% duty-cycle current-commutating passive mixer and a transimpedance amplifier,so as to achieve an RF front-end system of anti-interference,low noise and high linearity.Tapeout and test results show that the designed front-end system accomplishes the goals of 20 dB out-band interference rejection,44.98 dB gain and 2.03 dB noise figure at 2.4GHz with a － 7 dBm 3rd input intermodulation point ( IIP3) and a + 72 dBm 2nd input intermodulation point ( IIP2) being obtained,which means that the designed system needs no surface acoustic wave filter and is of anti-interference characteristic.In addition,the designed system has a power supply voltage of 1.2 V and a power consumption of 36mA.