Abstract: A flexible long-lasting clean energy power generation device with spontaneous moisture absorption is a multi-layer film structure including a hydrophilic support substrate, a conductive layer and a moisture absorbent layer. The conductive layer is coated on an outer side of the hydrophilic support substrate and has a first section and a second section, and the moisture absorbent layer is coated on the first section of the conductive layer, so that the flexible long-lasting clean energy power generation device is formed into an asymmetrical structure. The moisture absorbent layer captures moisture from the ambient environmental humidity, and the moisture forms a capillary pressure difference by a capillary action and an evaporation, so that water molecules and ions move from the wet area of the moisture absorbent layer to the dry area of the second section to form an electric potential difference.