When the traditional single-rod viscous baffle is subjected to a large impact, the flow velocity of the internal fluid medium through the annular gap or round hole is extremely high, which is prone to cavitation, vibration or noise. A single-rod baffle using a V-shaped throttling groove is proposed, which uses the diversion characteristics of the outlet of the V-shaped throttling groove and the variable overflow area to enhance the stability and damping performance of the baffle. In order to verify the stability of the flow field of the structural baffle in response to large impact, the RNGk-ε turbulence model of ANSYS Fluent software is used to simulate the flow field flow in the V-shaped throttling groove of the baffle, and the Mixture model is used to simulate the cavitation phenomenon inside the flow field. The results show that: 1) By comparing the openings of different throttle troughs, it is found that the positions and ranges of cavitation occur differently under the conditions of larger openings and smaller openings; 2) By comparing the opening angle of the throttling groove, it is found that the opening angle affects the position of the cavitation area of the piston wall; 3) By comparing the fluid media with different viscosities, it is found that the viscosity of the used medium has a significant impact on the occurrence of cavitation.