In order to explore the characteristics of the state change of micro-nano particles during the laser plasma shock wave cleaning process, cleaning experiments were carried out for Al micro-nano particles on the surface of single crystal silicon; combined with the plasma propagation law and finite element method, the internal stress and temperature changes of the particles were simulated under the circumstances, and the law of phase transition and evolution of particles was obtained. The results show that the number of large and medium particles is significantly reduced, and the size is changed from 0.5μm~3μm to 0.1μm~1μm; the change in the state of the particles is mainly caused by the instantaneous high temperature and high pressure of the shock wave, and the maximum stress in the particles reaches 1GPa. The maximum temperature reaches 1100K; therefore, the particles break and phase change under the action of the shock wave, and the number of fine particles increases and adheres to the sample surface, which increases the difficulty of cleaning. This research can provide reference for the theory and application of laser cleaning particles.