Abstract Tunable-focal length LC lens with hole-patterned electrode have been fabricated in this study. Liquid crystals (LCs) are excellent electro-optic materials with electrical and optical anisotropies. Their optical properties can easily be varied by external electric field. Hence according the electro-optic properties, we made the tunable LC lens. In this study a novel conoscopy method has been applied to analyze the LC lens. First, we study the causes of the focusing and the optical properties of LC lens, and measure the focal length with varying voltage. Second, by analyzing the figure patterns formed with conoscopy method. We study the LC molecules reorientation caused by the inhomogeneous electric field distribution. In order to improve the spoiled effect due to the subsidiary domain in the LC lens, three different structures of LC lens have been fabricated and the focusing effect has been discussed.