Abstract: Taking the vibration and noise in Reactor Cavity and Spent Fuel Pit Cooling and Treatment pipe line in nuclear power plant as an example,based on the actual experimental engineering parameters,the experimental studies on fluctuating pressure excitation and pipe vibration resulted from flow disturbance induced by single local resistance element-orifice plate are conducted under the condition of the different flow rate and the same back pressure.The pipe flow field and pressure field is numerically simulated,especially the flow station of orifice plate.The simulation results and experimental data are compared and analyzed.The research results show that the energy spectrum increases with the increasing of the degree of throttle of orifice plate.As the increasing of flow rate and fluid disturbance,the spectrum breadth of pressure fluctuate increases without the disturbance of other excitation source.