A band-gap reference circuit includes a proportioned current generating circuit, a startup circuit, a current mirror circuit, a high-order temperature compensation generating circuit and a reference generating circuit. The proportioned current generating circuit is configured to generate a current in direct proportion to the absolute temperature. The startup circuit is configured to start up the proportioned current generating circuit when the startup circuit is power on. The current mirror circuit is configured to reproduce a current which is the same as the current in direct proportion to the absolute temperature. The high-order temperature compensation generating circuit is configured to generate a compensation current of high-order temperature coefficient. The reference generating circuit is configured to add the voltage which is generated by the proportioned current generating circuit to a voltage of negative temperature coefficient according to a certain proportion, and output a reference voltage of zero temperature coefficient.