To obtain the deformation behavior in the laser forming, numerous experiments are needed. In the practical applications,sometimes the plates are huge and the expenses are high. To reduce the number and the expenses of the experiments,the similarity method is adopted, and the similarity conditions of temperature field are derived by equation analysis. To verify the validation of the similarity conditions, the numerical simulations of three plates that meet the similarity conditions are carried out. The simulation results suggest that the three plates have similar temperature and deformation fields. The method is of significance in reducing the experimental expenses and time for much larger plates.