The concept of Complex Distribution Grid (CDG) health diagnosis and evaluation is introduced. Health index system is used to describe performance of CDG based on the analogy between CDG health status and human health state. The index is screened by considering primary-secondary effect as well as internal and external influence factors. A quantitative reference frame is established to measure its health state. Its gap and changing trend are found by diagnostic analysis of the indicator system through the Analytic Hierarchy Process and Fuzzy Theory, and the suggestions on the anomalies are given out. The effectiveness of the diagnostic method is verified by analyzing certain real 10 kV distribution network including health assessment of the system in small time scales and health trend prediction in large time scales.