The utility model relates to a power plant heating steam supply flow measuring device based on heat balance. The power plant heating steam supply flow measuring device is composed of a sensor unit, a data acquiring unit connected with the sensor unit and a calculating and displaying unit in both-way connection with the data acquiring unit. The sensor unit is composed of a flow senor located on a heat-supply network circulating water pipe, a first pressure sensor, a first temperature sensor, a second temperature sensor located on a heat-supply network heater outlet circulating water pipe, a second pressure sensor, a third temperature sensor, a third pressure sensor and a fourth temperature sensor, wherein the first pressure sensor and the first temperature sensor are located on a heat-supply network heater inlet circulating water pipe, the second pressure sensor and the third temperature sensor are located on a heat-supply network heating steam supply pipe, and the third pressure sensor and the fourth temperature sensor are located on a heat-supply network heater outlet water drainage pipe. The outlet ends of the sensors are respectively connected with the input end of the data acquiring unit. The power plant heating steam supply flow measuring device has the advantages of achieving accurate real-time monitoring of power plant heating steam supply flow and being simple in overall structure and convenient to measure.