Heat energy and engine models of bucking process for continuous wave(CW) CO_2 laser irradiating thin metal tube are built with finite element method(FEM) of ABAQUS.On the models,the temperature,stress,residual stress distribution and bucking angles are simulated numerically,and the deformation mechanism caused by changing the parameters is researched.The experiments are designed according to the simulation.The results show that the bucking model built in the study is valid,and thd differences between the results of simulation and experiments are analyzed.