Abstract: In view of the characteristics of arc gouging,the temperature field of arc gouging was simulated with the method of deactivation of elements using FEM,and the influence of the temperature field on the microstructure of the groove was also researched.The studies show that the temperature fields of arc gouging change sharply,especially the cooling speeds exceed that of the welding processes.Because the high heat affected zone is very narrow,the microstructures changing zone of the groove is also narrow,and the main microstructure in this zone is fine martensite for 10Ni5CrMoV steel.