The invention relates to a method of increasing the energy storage density of a capacitor through atmospheric pressure low temperature plasmas. The method comprises the following steps: cleaning and drying a to-be-processed capacitor film; selecting atmospheric pressure low temperature plasma generation equipment, and placing the capacitor film in a plasma generation area of the atmospheric pressure low temperature plasma generation equipment; selecting types of a high-voltage power source, a predecessor and working gas, and adjusting discharge parameters and the flow speed of the working gas; and carrying out plasma deposition. Atmospheric pressure low temperature plasmas are utilized to process the capacitor film, the breakdown field intensity of the surface of the capacitor film reaches above 17%, and the energy storage density is increased by over 23%.