The invention discloses a source-load reserve coordination optimization method based on a generalized Benders decomposition method, which comprises the following steps of: firstly, linearizing the generation side operation and the reserve cost in sections, and based on the linearization, establishing a source-load reserve coordination optimization model, wherein the model is composed of an objective function and a constraint condition; Then, a generalized Benders decomposition method is proposed to solve the source-load-reserve cooperative optimization model, and the results are used to optimize the scheduling. The method of the invention reduces the computational complexity, has good convergence, and lays a good foundation for solving the standby cooperative optimization problem on a large scale.