With the development of aerospace and airspace technology,laser plasma propulsion has attracted more and more attention.Based on spatial distribution of the plasma from laser interacting with substance,in this paper,the power function relationship between ablation pressure of carbon target and laser intensity is deduced from microscopic,macroscopic and simplified models,the power indices are 0.60493,2/3 and 2/3,respectively.The experiment shows the power function relationship between the maximum deviation of carbon target and the laser energy,and the power index is 0.61936.The relative difference of power index between the experiment and the microscopic model is only about 2.32%,while the value between the experiment and the macroscopic or simplified model attains about 7.64%,this indicates the rationality of the microscopic model.However,either the macroscopic or the simplified model is also applicable to some extent that the error permits.The mechanism analysis of laser plasma ablation thrust has some guiding significance for engineering research.