The invention relates to a single-electrode generator based on double charge layer in a solution and a power generation method. The single-electrode generator is provided with a first component, a second component and an equipotential source, wherein the first component is composed of a first thin film layer and a first conductive layer attached to the back of the first thin film layer, and the surface of the first thin film layer carries positive charge or negative charge in water. The relative distance between the second component and the first thin film layer changes, double charge layer are formed between the charge carried on the surface of the first thin film layer and heterogeneous charge ions absorbed from the solution when the first component and the second component are separated, and the charge balance is maintained; and when the distance between the first component and the second component is close to 1[mu]m or below, the solution near the surface of the first thin film layer and the ions in the solution are discharged, and the positive charge or negative charge carried by the surface of the first thin film layer cannot be shielded by the heterogeneous charge ions in the solution, thereby inducing net charge in the first conductive layer, resulting in the generation of potential difference between the first conductive layer and the electrically connected equipotential source, and driving the flow of electrons in the connected external circuit so as to form current.