The utility model relates to a mechanical-to-electrical energy conversion device, and belongs to the energy technology field. The device includes a semiconductor substrate for a nanoscale fluid passage. The semiconductor substrate is disposed in a cavity filled with electrolyte. The cavity is provided with first and second surfaces respectively opposite to two surfaces of the semiconductor substrate and capable of moving relative to the semiconductor substrate after pressing. The two surfaces of the semiconductor substrate divide the cavity into the first surface and the second surface, and are fixedly connected respectively to positive and negative external electrode plates connected to the anode and cathode of a power supply. The mechanical-to-electrical energy conversion device not only has the significant advantages of simple structure and high conversion efficiency, but also achieves conversion of clean energy into electrical energy, thereby providing hopefully a novel energy conversion means for increasingly tense power supply. Meanwhile, the conversion from electrical energy to mechanical energy can effectively remove and filter toxic polluted charged particles in a solution, and a new idea is provided for wastewater treatment technology such as purification of water sources and the like.