The invention relates to a power distribution network health index assessment method comprising the following steps: 1, determining power distribution network health index connotation and purpose; 2, determining a power distribution network health index assessment object; 3, determining a power distribution network health index assessment index system; 4, evaluating a transformer and distribution equipment health index; 5, evaluating the power distribution network health index. In a long term, the reliability research pays more attention on a single device at certain moment, a single section (static state), a fault result, and a cause and effect relation; the novel method provides a colony equipment and network health index assessment method, can study the colony equipment and network dynamic health level and power supply reliability, can guide power distribution network planning and operation unkeep asset management, can provide equipment and network health status quantification analysis, and macroscopic and microscopic are combined to provide base theory and practical technical means.