Electric control focal length variable liquid lens

The utility model discloses an electric control focal length variable liquid lens, comprising a liquid lens which is a main body part, is arranged on a lens slide rail, and is connected with an electric injector; the liquid lens comprises two clamping cover rings, two layers of PDS films are clamped between the two clamping cover rings, and a gap between the two layers of films forms a liquid cavity. The electric injector comprises an injection guide pipe connected with the liquid injection hole, the rear portion of the injection guide pipe is connected with a liquid tank and an electric piston, and the single-chip microcomputer control module controls the electric piston to move. On the basis that the external structure is not changed, the zoom of the lens is realized by injecting and extracting liquid, and the problem that the focal length of an original single solid lens cannot be changed is solved; the liquid in the liquid lens can be flexibly replaced so as to adapt to different cost requirements and per