The invention provides a static safety probability assessment method of a new energy grid power system. A new energy force output model adopting wind speed, sunlight intensity and other meteorologicalelement time period features comprehensively reflects weather random fluctuation features and time change rules, the nondeterminacy of system operation is reflected through a probabilistic load flowmethod based on Monte Carlo simulation, and the new energy force output model and the probabilistic load flow method are combined to set up the static safety probability assessment method of the new energy grid power system. A system load flow out-of-limit probability index is put forward to analyze the weak link and high-risk time frame of the system. A system N-1 risk assessment index is put forward to assess the system N-1 risk level and the risk change condition caused by new energy access scene changes. Compared with traditional and deterministic system static safety analysis, the nondeterminacy of the new energy grid power system is considered, the probability of static safety is assessed through the probability assessment method and an index assessment system, more comprehensive information is provided for system operation, and reference is provided for medium-term and long-term planning, scheduling and the like of the power system.