A bandgap reference circuit based on switched capacitor is presented in this paper.It uses cleverly equivalent resistor of capacitor and switch to reach a low quiescent current and a well temperature coefficient.And the technology of auto-zero is used to overcome the offset disadvantage of linear reference and cancel the offset voltage of amplifier.So the offset precision of output voltage can be improved.The circuit was designed and implemented in 0.5 μ m CMOS technology.The temperature coefficient is around 29ppm/℃

while the reference voltage variation is only 0.4mv with a 20mv input offset voltage.