In order to improve the accuracy and the speed of reconstructing an image, the digital holographic generalized linear reconstructing algorithm based on homomorphic signal processing is proposed. By using the pre-magnification digital holographic imaging system and the principle of homomorphic signal processing, the proposed algorithm is analyzed theoretically. The achieving condition for and reconstructing process of the proposed algorithm is presented. Then the theoretical results are demonstrated by simulations and experimental data. Results show that the zero-order term of digital hologram frequency spectrum can be eliminated effectively by the proposed algorithm so as to realize the high-precision reconstruction of the digital hologram. Because a whole quadrant is chosen as the filtered area, the manual frequency filtering operation needed in common linear reconstructing algorithm is avoided and then the reconstructing speed is improved greatly. Meanwhile, the high-frequency component of the reconstructed original image can be reserved up to the hilt so that the high resolution image can be achieved.