The invention relates to a large-scale wind power-containing power transmission network planning system considering risks. The large-scale wind power-containing power transmission network planning system comprises a database module, an input module, an analysis module, a planning module and an output module, wherein the database module is used for storing wind speed data, load data and power equipment data; the input module is used for acquiring required data from the database module and the outside of the system; the analysis module is used for calculating an economic risk index, a technical risk index and investment cost of a planning scheme according to the input data and acquiring security constraint conditions of a power transmission network; the planning module is used for building a power transmission network planning model, determining the power transmission network planning model according to the economic risk index, the technical risk index, the investment cost and the security constraint conditions of the power transmission network, obtained by the analysis module, and acquiring the power transmission network planning result considering the economic risk and the technical risk; and the output module is used for outputting the power transmission network planning result. Compared with the prior art, the risks caused by wind farm output uncertainty can be lowered when the investment cost is controlled; and the large-scale wind power-containing power transmission network planning system has the advantages of high efficiency, comprehensive factor consideration and the like.