The present invention relates to a preparation technique of an excitation system tripping circuit. The excitation system tripping circuit is prepared by determining a design scheme of two tripping circuits, selecting the type and purchasing a tripping relay, designing a principle wiring diagram and an assembly diagram of the tripping circuits, carrying out the monomer technology test on the tripping relay, installing and wiring the tripping relay, and testing and jointly debugging the tripping circuits. According to the present invention, the type selection of the large-power tripping relay is crucial, and the tripping relay still can act effectively when the action power is 6-7 W, the response time is 10 ms, and the operation voltage is within a range of 55%-70%, thereby satisfying the stipulation of the state grid corporation 18 grid important anti-accident measures-relay protection professional and key implementation requirements, and eliminating the potential safety hazard of the conventional tripping circuit. The preparation technique of the present invention guarantees the accurate action of the tripping relay, enables the operation reliability of an excitation system to be improved, is low in cost and small in workload, and is easy to implement.