为了准确重建微小物体三维物场，采用理论分析与计算机模拟相结合的方法，研究了如何用准直光重建大数值孔径数字全息图，分析了用球面参考光波再现失效的原因，得到了位相重建的表达式；分析了由于记录距离和参考点源偏置的测量误差而导致位相重建像的畸变，作了计算机模拟验证。结果表明，对于强度重建，只要能够记录高质量的全息图，就可以得到准确的再现结果；而对于三维物场重建，只有准确测量记录距离和参考点源的偏置，才能得到准确的再现结果；由于距离的测量误差，导致再现光波场的位相分布出现了二次函数调制畸变，因此，实验过程中精确测量这两个参量是至关重要的。

In order to reconstruct three-dimension micro-object wave field accurately,the reconstruction method with collimating reference wave to reconstruct digital hologram with large numerical aperture was studied by using Fresnel diffraction formula and sampling theorem. The reason that spherical reference wave can't be used to reconstruct a large numerical aperture hologram was analyzed. The expression of reconstructed phase image was presented. As result of the measure error of the recording distance and the offset of the point source,the distortion of the phase image reconstructed with collimating reference wave was also analyzed. Both theoretical analysis and computer simulation show that accurate intensity reconstruction can be obtained as long as a high quality hologram is recorded. Only if the recording distance and the offset of the point source are accurately measured,the correct phase reconstruction can be obtained. Due to a measure error,a quadratic function distortion of the reconstructed phase distribution appears. So it is important to measure the recording parameters accurately in experiment.