Abstract: In view of the problem that the neutral grounding resistance of 10 kV distribution transformer is too large, which is easy to affect the power quality of low-voltage distribution network users, this paper establishes mathematical models of output phase voltage, grounding resistance voltage（neutral grounding resistance to ground voltage） and grounding current（neutral grounding resistance to ground current） of low-voltage distribution network when the three-phase load is balanced and the three-phase load is unbalanced Type. A Simulink system simulation model of the output phase voltage, earth resistance voltage and earth current of the low-voltage distribution network when the three-phase load is balanced and when the three-phase load is unbalanced is established using MATLAB simulation software. By making the four cases of grounding resistance RJ given four grade values: 200 Ω, 50 Ω, 12.5 Ω, 3.125 Ω, the three-phase imbalance of the low-voltage distribution network is simulated and analyzed, and the analysis results of the influence of the neutral point ground resistance of the 10 kV distribution transformer on the three-phase imbalance are more accurately obtained. It is proposed that the neutral point grounding resistance of 10 kV distribution transformer can be improved to be less than 4 Ω, so as to solve the problem that the user’s electrical equipment is damaged when the three-phase load of low-voltage distribution network is unbalanced.