Abstract: The common-source amplifier is one of the most basic and important parts of analog integrated circuits. To optimize the design of common-source amplifier, the mathematical model of multiobjective optimization is built based on the theoretical analysis of its operational principle, and the normalized equation is applied to make the fitness function more applicable. Genetic algorithm is used to solve the multiobjective optimization model, and the optimization of the common-source amplifier design is completed finally. The simulation experiment is made to verify the validity of the optimization method based on the standard 0.18 μm CMOS technology, and the simulation results show that the proposed modeling and optimizing method can provide fast and accurate optimization for the design of amplifiers in analog integrated circuits.