The invention relates to a determination device for the Seebeck coefficient of a flexible thin film material. The determination device comprises an infrared thermal imager, a sample to be measured, a heating assembly, a vacuum pump, a direct-current power supply, wires, a digital source, electrodes, a thermal dissipation assembly, a vacuum box, an infrared window, a base and a support; the vacuum box is installed on the base, the infrared window is arranged on the top of the vacuum box, the heating assembly and the thermal dissipation assembly are installed on the positions, in the vacuum box, of the base and used for suspending the sample to be measured, the vacuum pump connected with the vacuum box is installed at the side of the base and used for ensuring that the sample to be measured is located in a vacuum environment, the infrared thermal imager is installed on the base through the support and located over the infrared window, the direct-current power supply is connected with the heating assembly and used for supplying power to the heating assembly, and the digital source is connected with the two ends of the sample to be measured through the wires and the electrodes. The determination device is simple in structure, easy and convenient to operate, low in cost and suitable for being easily used and popularized in the industrial field and the scientific research field.