A device for automatically adjusting the angle of solar panel is designed by using the temperature difference effect produced by solar energy. The device can automatically sense the angle and intensity of sunlight to form a temperature difference. The temperature difference is converted into a pressure difference by a temperature difference collector, and then the pressure is converted into the power needed to adjust the angle of solar panel by a pneumatic push rod, so as to realize the automatic light alignment of solar panel. The temperature sensing and pressure forming automatic light tracing device designed by this device has better usability and popularization. It can be applied to the automatic light tracing of solar panel, effectively solve the cosine effect caused by the change of solar light angle, and reduce the problem of low power generation efficiency caused by light tilt and short life of traditional electric control light tracing device.