The invention discloses a high-efficiency ternary organic solar cell and a preparation method thereof. The active layer of the organic solar cell is obtained by blending a donor material and a receptor material. A ternary organic solar cell containing both non-fullerene and fullerene receptors is prepared by introducing a third component, fullerene acceptor, into the active layer of a binary non-fullerene organic solar cell. The addition of the fullerene receptor not only broadens the optical absorption spectrum of a device and increases the short-circuit current density, but also modifies theshape of the active layer, and finally improves the photoelectric conversion efficiency of the organic solar cell. Further, the active layer of the ternary organic solar cell can be processed at roomtemperature, and a solution can be formed into a film by spin coating, blade coating, and screen printing. Without any physical optimization method, the method can improve the efficiency of the device, reduces the manufacturing cost of the organic solar cell, and is suitable for the roll-to-roll production process.