A conventional band-gap reference circuit normally comprises a startup circuit, a current generating circuit, current mirror circuit and a reference generating circuit. A startup circuit is configured to generate a current when electrified. A current generating circuit is configured to generate such current as is in direct proportion to absolute temperature. A current mirror circuit is configured to reproduce an exact current. A reference generating circuit is applied to add the voltage caused by such current as is replicated to the voltage of negative temperature coefficient in a certain relation and output a reference voltage featuring zero temperature coefficient. Although a traditional band-gap reference circuit compensates the temperature of the first order, the reference voltage does not remain constant within full temperature range as base-emitter junction voltage of bipolar transistor is related to the higher orders of temperature. So the circuit fails to meet the requirement of high speed high resolution A/D and D/A converters for a stable temperature as a reference signal.