Abstract: A low mismatch Curvature-Compensated CMOS bandgap reference by the mechanism of chopper modulator, we use a first-order folding amplifier, which has a simple structure, low power consumption and smaller layout area than second-order, it still has a good gain.We use second-order current compensation, make the BGR a better temperature coefficient and the system is stable.We use a standard 0.5μm CMOS process to simulate the op-amp circuit and bandgap reference circuit.The circuit delivers an output voltage of 1.17V, and achieves temperature coefficient of 4.7 ppm over-20 ℃ to 120 ℃ We can choose a different process and passive resistance to make the different reference voltage, temperature coefficient is still enough to meet the actual needs.