Abstract: The numerial analysis of the stress and strain cycles during TIG spot welding of thin plate are presented in this paper. Three methods are used in comparison; method of numerical integration of differential equations (before unloading), finite element method and finite difference method. In this particaular case of axially symmetrical temp erature distribution in a thin disk, the finite difference method has advantages that the computer program could be simplified; consequently, the machine-time for computation could be reduced; and the result with higher accuracy could be obtained. In the developed computer program the material proper ties as function of temperature and melting-solidifying processes of molten zone are taken into consideration. The results of calculations are in a fairly good agreement with the experimental data.