The invention discloses an important user power supply risk assessment method based on a unit system distribution network model, Based on the unit distribution network model, As that pow supply unit is taken as the smallest logical analysis unit to obtain the model and the operation mode, search by topology, level by level, combined with power traceability results, Evaluating critical user power supply risks based on a risk rulebase, by automatically generating the power supply path diagram of the important users, the real-time monitoring of the power supply risk of the important users can beachieved, so as to help the operators to optimize the normal operation mode of the electric distribution network in time, adjust the operation strategy of the distribution network, prepare for the risk prevention and control of the important users, and effectively ensure the safety of the power consumption of the important power users.