The suppression technology of pressure oscillation is one of diffi-culty of regenerative liquid propellant guns. It is reported that the inspiringmechanism of pressure oscillation of RLPG can be broken by change of inher-ent frequency of mechanical vibration of regenerative injection piston system.The experiments show that amplitude of pressure oscillation can be suppressedby using this way. The research results have instructive significance to interiorballistic design of RLPG.