The graduated project of NFU Dept. of Electronic Engineering is two different kinds of integrated circuit design that have been presented in this research project. One of them is an Operation amplifier,and the other one is a Differential output reference voltage circuit. Use the TSMC 0.35, 0.18 micro-meter process parameter to simulate and implement the presented circuits. All the simulation results are consistent with the theoretical analysis, and also prove the feasibility of the presented circuits.