In this paper, we propose a new reconstruction method for the synthetic aperture on-axis digital hologram with seams, and then evaluate it thoroughly. This method combines the principles of synthetic aperture and phase retrieval. It is applied to the experiment of the particle field detection. In the experiment, the pictures depict the particle is not only clearly visible at the normal region but also at the seams. With error analysis in reconstruction, method of correcting stitching errors improves accuracy furtherly. Therefore, the method proposed in this paper can effectively restrain the influence on the reconstructed image due to the loss of information at the seams and can achieve high-quality reconstructed image from the seamed stitching synthetic aperture on-axis digital hologram. It can be widely used in the diagnostic domain with high resolution and large visual field.