Based on a 018 μm CMOS process, a two-stage ultra-wideband low noise amplifier (LNA) was designed for the applications in wireless communication bands below 10 GHz. The first stage, based on the complementary common-source stage, introduced the structures of resistor feedback, inductance peaking technology and pseudo-resistor to improve the bandwidth and gain while reducing noise. The second stage introduced inductance peaking technology, gain auxiliary stage and buffer stage on the basis of common-source amplification, which were mainly used to increase the circuit gain and improve the output broadband matching characteristics. The simulation results showed that the gain was 14.2±0.2 dB, the noise figure (NF) was less than 3.97 dB, and the overall power consumption was 12.9 mW within the frequency range of 0.5~9.2 GHz.