In order to reduce the damage to fluidic element caused by stress waves from impacting cylinder in a return-stroke of the fluidic hydraulic hammer piston to prolong the life of the fluidic element, a disc spring buffer structure in the cylinder was proposed to absorb the striking energy of hammer stroke. The simulation analysis was carried out on the piston return-stroke by the means of LS-DYNA display dynamic analysis to study the effect of the disc spring buffer on the stress state of bi-stable fluidic amplifier. The results show the feasiblility of disc spring buffer structure in the actual work of hydraulic hammer, the maximum stress can be decreased by 40%～57% in bi-stable fluidic amplifier and the stress state of fluidic element is effectively improved.