In order to avoid the longitudinal vibration and structural damage of the disc spring of the hydraulic plunger bottom cover tightener under the action of alternating load for a long time,combined with the actual project,taking the disc spring in hydraulic device as the research object,using the physical test and vibration mechanics theory,the load-displacement curves and dynamic and static stiffness ratios of different combination types of disc spring were obtained,so as to determine the appropriate combination type of disc spring.Then the harmonic response analysis was carried out to obtain the response frequency-amplitude curves.The results show that friction damping is the main factor that causes the load displacement characteristic curves of disc spring to form a hysteretic region;the curve is nearly linear when the load comparison is small,and presents nonlinear characteristics with the increase of load;the ratio of dynamic and static stiffness of the tightener decreases with the increase of the number of disc spring pairs;the resonance amplitude and von Mises stress are the largest when the external excitation frequency is 2 100 Hz,and the position III of disc spring is the dangerous point of resonance.