Abstract: In this paper, the reliability probability model of line fault under different neutral grounding modes is established by synthetically considering the causes of line tripping under different neutral grounding modes. According to the characteristics of three typical distribution network structures, considering the influence of different grid structures on the power supply to users, finally, the reliability evaluation model of distribution network considering the neutral grounding mode and the grid structure is established. Taking trunk type and ring type distribution network as examples, the reliability of two typical distribution network connections under different neutral grounding modes is obtained, and two neutral grounding modes are objectively evaluated. Lower distribution network power supply reliability level.