In this paper, a low-power ultra- wideband (UWB) lownoise amplifier (LNA) is proposed. Here, we propose a structure to combine the common gate with band pass filters, which can reduce parasitic capacitance of the transistor and to achieve input wideband matching. The π-section LC network technique is employed in the LNA to achieve sufficient fiat gain. A bias resistor of large value is placed between the source and the body nodes to prevent body effect and reduce noise. Numerical simulation based on TSM.C 0.18μm 1P6M process. It achieved 10.0-12.4dB gain from 3 GHz to 10.6 GHz and 3.25 dB noise figure in 8.5 GHz, operates from 1.5V power supply, and dissipates 3 mW without the output buffer.