A reference circuit for providing a precision voltage and a precision current includes a bandgap voltage reference circuit, a positive temperature coefficient calibrating circuit, a threshold voltage superposing circuit and precision current generator interconnected in cascade. From the bandgap voltage reference circuit, a bandgap voltage is outputted as the precision voltage, and a PTAT current is outputted to the positive temperature coefficient calibrating circuit along with the bandgap voltage for generating a PTAT voltage. In response to the PTAT voltage from the positive temperature coefficient calibrating circuit, the threshold voltage superposing circuit generates a first voltage which is equal to the PTAT voltage plus a threshold voltage. Then the precision current generator outputs a reference current as the precision current in response to the first voltage.