Ablated particles and ambient gas atoms are assumed to be rigidity-spheres. In order to investigate the influence of substrate on the density-reversion time of environment,the propagation of Si particles generated by single pulsed laser ablation through ambient He gas with 1000 Pa is simulated via Monte Carlo method. The results show that the density-reversion time of the environment is 1713.2 μs and 1663.2 μs respectively when the Si particles are absorbed and rebounded completely by substrate. With increasing critical adsorbing velocities of the substrate,the density-reversion time firstly increases and then decreases.