The invention relates to the field of water resources and hydropower, in particular to a hydropower side slope supporting structure. The hydropower side slope supporting structure can eliminate the adverse effects caused by project side slope dangerous rock mass on the safety of a project more conveniently and more economically. The hydropower side slope supporting structure comprises a side slope. The downhill position of the side slope is provided with a project head pivot region. The uphill position of the side slope is provided with at least one passive protection net structure. A rock-filled concrete structure is fixedly arranged on the slope surface located between the passive protection net structure and the project head pivot region. According to the hydropower side slope supporting structure, the rock-filled concrete structure and the passive protection net structure are arranged on the slope; the rock-filled concrete pouring method avoids the adverse effects of the project side slope dangerous rock mass on the project safety, so that the risk of the project is reduced, and the hydropower side slope supporting structure is particularly suitable for the side slope protection of hydropower projects.