Abstract: Aiming at SiGe HBTs power devices,the breakdown voltage,stability in working frequency,maximum optimization load impedance and so on are researched based on a 0.18 μm SiGe BiCMOS technology in a domestic foundry.And it gives the design and optimization process of power amplifier.The performance of frequency and maximum power gain of power SiGe HBTs in two configuration common emitter and common base are compared.A class A power amplifier with all devices integrated on chip is achieved which will be used in 2.4GHz wireless communication field.Measurement results show that S₁₁ <-13 dB,S₂₂ <-10 dB,S₂₁=13.8 dB,output power 1 dB compressed is 10.97 dBm,and saturation output power is 16.7 dBm.