The invention relates to a transmission system planning method using distributionlly robust optimization, and provides a transmission system planning method using distributionlly robust optimization. A transmission network planning scheme which meets the requirements of safe operation of a transmission system under any possible probability distribution realization scenario of wind power and minimizes the investment cost is selected. According to the technical scheme of the invention, the method comprises the following steps: (1) a distributionlly robust chance-constrained optimization model of transmission system planning is established; (2) random variables in the distributionlly robust chance-constrained optimization model are eliminated by making use of the complementary features of S-lemma and the matrix Schur, and the distributionlly robust chance-constrained optimization model is converted into a deterministic model containing a matrix inequality; and (3) the model obtained in step (2) is solved by a genetic algorithm based on linear matrix inequality optimization, and the final transmission system planning scheme is obtained according to the requirements of power system operation. The transmission system planning method using distributionlly robust optimization of the invention is mainly applicable to power grid planning and construction.