Digital holographic microscopy has been a powerful metrological technique for phase-contrast imaging.However inherent phase aberrations always exist and degrade the quality of the phase-contrast images.A surface fitting method based on an improved mathematic model is proposed,which can be used to remove the phase aberrations without any pre-knowledge of the setup or manual operation.The improved mathematic model includes not only the usual terms but also the cross terms and the high order terms to describe the phase aberrations with high accuracy.Meanwhile,a non-iterative algorithm is used to solve the parametersand thus less computational load is imposed.The proposed method is applied to the live imaging of cells.The experimental results verify its validity.Digital holographic microscopy (DHM) has been a powerful metrological technique which permits realtime quantitative phase-contrast imaging.The hologram is recorded by a CCD or a CMOS camera while the reconstruction is performed numerically.Many digital signal processing techniques have been introduced to enhance DHM for speckle removal,[1,2] aperture truncation,[3] phase unwrapping[4,5] etc.It has been widely used in biomedical optics for quantitative phase-contrast imaging,[6] identification[7,8] and tracking of organisms.[9]