Abstract: Aiming at the impedance matching problem of 3G base RF LNA circuit, an impedance matching optical design based on EDA software has been given in this paper.Firstly, the small signal S parameters of the LNA are utilized to make the file of S2P, which provided by manufacturers modeling.Secondly, the model of input and output matched circuits in Ansoft designer is built to optimize the input and the output circuits according to the maxinization gain and noise.The simulation results show that the Gain of optimized LNA is improved, at the same time reflectance have been improved significantly.This method is one of the efficient ways to solve the impendence matching problem of 3G Base RF LNA.