Abstract: In this paper the similitude temperature field is considered as prerequisite to the similitude stress and strain fields because welding heat effect is the essential reason for residual strain and stress.The similitude principles for welding temperature field are deduced by dimensional analysis method.On the basis of similitude temperature field,the correspondence relationship between stress and strain fields is deduced by equatioanl analysis method.The essential conditions of Gauss heat resource for similitude temperature field are also deduced for numerical simulation.In this paper plates with surfacing welding are simulated by numerical method to testify feasibility of the deduced similitude principles and the results show satisfactory coincidences.