To address the dynamic response problem of the hydraulic anti-backward tilting device（HATD）for sudden unloading of a crane，a characteristic modeling method of the HATD is proposed. The HATD is simplified into a model composed of a fixed damping pipeline and a variable damping valve. The characteristics of the pipeline and the cartridge valve are respectively analyzed theoretically，and a general method for describing the buffering characteristics of the HATD is established. Through a series of characteristic tests，the damping force components in the buffer force are separated，and the parameters describing the damping characteristics of the HATD are identified. The HATD model is integrated into the rigid-flexible coupling model of the crane as a virtual force varying with speed to form a virtual prototype of the crane. Through a series of unloading impact simulations，a simulation curve describing the relationship between unloading load and damping force is obtained，and the accuracy of the simulation model is verified through crane anti-backward tilting tests. This experimental modeling method can provide a reference for accurately solving the complex dynamic response between a type of elastic structure and a hydraulic buffer system.