The invention discloses a testing power supply for single phase watt hour meter calibration, comprising a controller, a voltage output circuit, a current output circuit, an output voltage measurementcircuit and an output current measurement circuit, wherein the output voltage measurement circuit is used for measuring an analog voltage signal output by the voltage output circuit to obtain a voltage measurement parameter and sending the voltage measurement parameter to the controller, the output current measurement circuit is used for measuring an analog current signal output by the current output circuit to obtain a current measurement parameter and sending the current measurement parameter to the controller, so that the controller adjusts a digital voltage signal and a digital current signal generated and output by the controller according to the voltage measurement parameter and the current measurement parameter. The testing power supply can effectively guarantee the output bandwidth and improve the output accuracy and stability. The invention further discloses a single phase watt hour meter calibration device, which also has the above technical effects.