We propose a new correction method for the splicing dislocation of sub-holograms in synthetic aperture digital holography. By adjusting the splicing distances between sub-holograms during the numerical reconstruction process using the convolution approach, the influence of non-paraxial aberration for the quality of the synthetic reconstructed image is avoided and synthetic reconstructed images corresponding to different splicing distances are obtained. Then, the accurate splicing distance between sub-holograms is determined by evaluating the quality of the corresponding synthetic reconstructed images. Accurate correction for the splicing dislocation of sub-holograms is achieved and high-quality reconstructed images without nonparaxial aberration are obtained.