The invention relates to the preparation technology of a micro-nano device and particularly refers to a technical method and process for preparing micro-nano lenses by using micro-nano droplets to dissolve polymer films by batch. The method comprises steps that firstly, a polystyrene (PS) film is spin-coated on a substrate; secondly, the PS film is immersed in the toluene-ethanol mixed solution, then a drop of deionized water is dropped into the mixed solution, at the same time, toluene precipitates, the PS Film is dissolved, and toluene-PS mixed droplets are generated in batch; thirdly, the toluene in the toluene-PS mixed droplets dissolves into the solution by itself, and the micro-nano lenses of the PS material are obtained in large quantities on the substrate. The method is advantagedin that the preparation process is simple, and controllability of the size, density and the shape of the micro-nano lenses is good.