The invention relates to an amplifying, mixing and filtering device for a GNSS receiving set. The amplifying, mixing and filtering device comprises a high gain and gain controllable low noise amplifier, a passive orthogonal mixer assembly and a multi-phase filter which are sequentially connected. The device adopts the novel low noise amplifier which adopts a current source load, so that the gain is increased greatly, and the gain controllable function is realized. Simultaneously, compared with a conventional lower noise amplifier with an inductive load, the manufacturing cost is reduced substantially due to the fact that the low noise amplifier doesn't comprise a load inductor with a larger chip area. Due to the high gain of the low noise amplifier, the noise margin of a circuit to a post-module is increased, so that two later orthogonal demodulation mixers of the circuit can adopt the passive frequency mixer and the multi-phase filter which are free of current consumption, and the power consumption is reduced. By means of the high gain and gain adjustable function of the circuit, the design requirement of the post-module is reduced, and the overall power consumption is further reduced.