Abstract: The influence the stress fields of air-arc cutting for 10Ni5CrMoV steel plates are simulated using finite element method and the simulating results are according well with the experiments results.The stress fields of air-arc cutting for 10Ni5CrMoV steel plates and the mechanics of influences on initial stress fields of air-arc cutting are studied further.The results show that the stable stress fields of air-arc cutting are similar to that of the butt plates welding.There are tensile stresses near the groove and then they turn low gradually,and finally the transversal stresses approach zero stress while the longitudinal stress change to compressive stress.The influence of air-arc cutting on the initial stress fields contain two aspects:1) the stresses near the groove are released because of the metal materials wiped away;2) the thermal function of the arc made a higher tensile stress existed near the groove,and it is more intense than the former.