An electrically controlled continuously focusing lens was introduced based on Polymer Dispersed Liquid Crystal (PDLC). Etching a hole on the upper surface of the electrode attaching to the PDLC cell to form an asymmetric electrode, a non-uniform electric field was induced. Then the non-uniform distribution of the refractive index in the PDLC cell was generated and a controlled zoom lens was formed. The basic principle of the focusing lens was also introduced, the effects of the lens aperture on the focal length of the PDLC lens were analyzed, and the relation between the focal length and voltage was measured with the diameter of 3 mm and 6 mm respectively. The results show that, with voltage ranging from 50 V to 170 V, the focal length of the PDLC lens was reduced from 1.361 63 m to 0.429 21 m in the diameter 3 mm or from 1.769 92 m to 0.548 43 m in the diameter 6 mm of the hole.