In synthetic aperture integral imaging system (SAII), a camera array, replacing lenslet array, is employed to obtain highresolution elemental images with multiple perspective. However, the SAII system still suffer from the limitation of depth of field (DoF). In this paper, we present a multi-focus elemental image fusion method by using NSCT to solve limitation of DoF problem. In proposed method, the depth estimation are achieved to register elemental images. Then, a fusion method based on non sub-sampled contourlet transform (NSCT) is employed to obtain full-focus elemental images. Finally, the resolution enhanced 3D images are reconstructed by using the full-focus elemental images. To show the feasibility of the proposed method, the preliminary experiments are carried out.