Through the detailed analysis of the parasitic effect of ESD protection on the noise performance of low noise amplifier (LNA), a new noise optimization technique for LNA with ESD protection is proposed, and concrete design formulas are presented.The LNA designed by this optimization technique can approach to or equal to the minimum noise figure of a single transistor. Simulation is carried out under 0.25μm CMOS process, the results indicate that the designed LNA can approach to the minimum noise figure under different power consumptions, therefore the effectiveness of the proposed optimization technique is verified.The proposed optimization technique can be widely used in the design of the LNA.