Based on the detailed analysis of fault component phase selection principle, the traditional ground short-circuit criterion of phase selection element based on faulty components is improved. The improved criterion only uses the phase difference between the negative sequence faulty components current phase and the positive sequence faulty components current phase and adds the threshold judgment of the zero sequence voltage component to distinguish the ground fault. It avoids the shortcomings of misjudgment since the zero sequence current distribution factor is not equal to its positive and negative ones in the traditional ground short-circuit criteria as well as simplifies the phase selection process. Simulation results show that the improved criterion is valid and stable. This work is supported by National Natural Science Foundation of China (No. 6172032).