The invention discloses a cross-region wind power installed capacity coordinated planning method which includes the steps of obtaining related data, constructing a calculation model, calculating a wind power combination effective frontier curve, determining a planning result and the like. According to the cross-region wind power installed capacity coordinated planning method, the wind power installed capacity of different regions is planned in a united mode based on an investment combination theory, wind power total contribution fluctuation is effectively reduced, and total peak pitching capacity demands of a system are reduced. The wind power installed capacity of the various regions under the condition that wind power combination quality factors are maximum serves as final optimized results, and the credibility of the wind power capacity and wind power fluctuation are considered to the maximum degree. The top limitation and the bottom limitation of the wind power installed capacity of the various regions are set, conditions, such as electric power network structures, load levels and government policies, of the various regions are sufficiently considered, and the planning result is close to the reality.