Abstract: It is very effective to selecte and to optimize welding parameters by the method of computer simulation. Increasing the reliability and adaptability of calculation model is the prerequisite of expanding its application limits. The method that on-line identifies parameters of the model through the information of temperature on the welding bead surface and thus increases adaptability of model was discussed in the paper. On the basis of mentioned above the optimized welding parameters for given required value of molten pool sizes were seleeted for different materials. The results of experiments showed that the model identified can be adapted to the changes of material and welding conditions and give suitable welding parameters.