In different unwrapping algorithms, the minimum cost flow (MCF) unwrapping method can limit the long-range diffusion of the residue error. Further, it can first limit the error to the low coherent region, which ensures that the unwrapping results in the high coherence region are not disturbed, and its accuracy is high. However, when the number of residues is large, the calculation efficiency is very low. To decrease the unwrapping time, a residue preprocessing method is proposed. In this method, the residues are regarded as positive and negative charges. Moreover, the electric field force is used to guide the residues with different signs close to each other to mutually offset, thus significantly reducing the number of residues and improving the efficiency of unwrapping calculations. Simulated and experimental data show that the residue preprocessing has little influence on the phase unwrapping accuracy. When the number of residues exceeds 3000, the residue preprocessing significantly improves the phase unwrapping efficiency.