In this paper, we present a novel three-dimensional (3D) sensing system which can demonstrate 3D acquisition. The proposed system is using an electronically tunable liquid crystal (LC) lens with axially distributed sensing method. Therefore, multiple 2D images with slightly different perspectives by varying the focal lengths of the LC lens without mechanical movements of an image sensor can be recorded. And then the 3D images are further reconstructed according to the ray-back projection algorithm. The preliminary functionalities are also demonstrated in this paper. We believe that our proposed system may useful for a compact 3D sensing camera system.