The invention discloses a moisture power generation method and device. The method includes the following steps: pouring a polymer solution into a culture dish and then placing the culture dish in a drying oven to prepare a polymer power generation film; placing the polymer power generation film on a moisture-insulated metal electrode, and disposing a porous top electrode above the polymer power generation film to protect a film form of the polymer power generation film and to transmit moisture; applying moisture stimulation to an external single direction of the metal electrode to induce separation of positive and negative ion pairs in the polymer power generation film and to release freely moving current carriers; and diffusing from a high concentration area to a low concentration area bythe current carriers to generate a potential difference and an electric current, thereby outputting electric energy to the outside. The method adopts a polymer material which is simple and easy to obtain and can be bent, stretched or even self-repaired, can achieve moisture control by simultaneously using orientation moisture stimulation, does not require usage of high-cost lasers, is simple in test method, does not require usage of other expensive external equipment for a test process, and has the advantage of large-scale integration.