Provided is a method for separating a nanogenerator, which includes laminating a buffer layer on a sacrificial substrate, making a nanogenerator on the buffer layer, laminating a metal layer on the nanogenerator and separating the nanogenerator from the buffer layer.Here, a nanogenerator is separated by using a stress difference between the sacrificial substrate and the metal layer, instead of an existing method in which a nanogenerator is separated from the sacrificial substrate by means of wet etching or the like. In particular, according to a difference between a tensile stress at the metal layer such as nickel and a compressive stress at the lower silicon substrate, the nanogenerator is intactly separated from the silicon oxide layer serving as a buffer layer. Therefore, the nanogenerator may be separated from the sacrificial substrate in a mechanical way, which is safer and more economic in comparison to an existing chemical separation method using an etching solution. Further, it is also possible to avoid a damage of the nanogenerator caused by an etching solution.