The current measurement methods of resistance ratio cannot meet the calibration requirements of high accuracy and full range differential resistance reading instrument.Two methods based on the meas-urement principle of differential resistor reading instruments were proposed to calibrate the resistance ratio indication error.These methods are direct measurement method and comparison measurement meth-od.These methods were compared and verified.The uncertainties are evaluated.The result shows that the absolute value of the difference between the measurement results of the two methods is less than 7 x 10-5,and the normalized deviation value is less than 1,which verified the consistence of these measuring methods.Both methods can be used for the measurement of the resistance ratio indication error.