Energy-saving method for oil pumping unit

The energy-saving method for oil pumping unit is to install between the medium output of oil Christmas tree and the input of medium conveying pipeline one energy-saving sensor with signal output connected to the input of computerized control cabinet. An embodiment example of the energy-saving sensor for oil pumping unit includes non-return valve, sensor, air compressor, and oil, water and gas discriminator connected together. In the valve cavity of the non-return valve, petroleum heater and thermocouple may be mounted. By means of the present invention, the oil pumping unit will run in the case of existing oil in the well and stop if no oil, and this can avoid energy waste.