The bandgap reference technique is one of the most widely used methods to provide a temperature-independent reference voltage in almost all electronic products and ICs from the mobile devices, the desktop equipment and to the infrastructure outdoors. In varying ambient temperature environment, a constantly stable current and voltage reference is vital to make sure the functionality and performance of other circuits relying on it. This project investigates the theorem and circuit structure to build a voltage reference using industrial design methodology including simulation, layout, physical verification for CMOS IC technology. The project also includes a hands-on experience to build the circuits through discrete components to measure, tune and data collection so as to understand the theory of bandgap reference.