The vibration model of Mechanical Rapping Ash Removal Devices was built based on the one-dimensional wave equation. According to special boundary conditions of the stricken rod, accurate analytical expressions of displacement, velocity, stress distribution as well as the impact duration time, when the stricken rod was impacted by transitive rod, were deduced. Furthermore, the obtained analytical expressions was verified by the simulated results by finite element software ansys/ls-dyna under actual operation conditions of rapping devices, and a good agreement was found.