This research presents a study with the help of Finite Element Method and the use of CATIA V5 program to know the behavior of a permissible link - column used in metal structures at high temperatures (on fire). In this article we will present an analysis using the finite element method using the CATIA V5 program for the effect of different engineering parameters (plate thickness, screw diameter, reinforcement nerves) on the behavior of joints used in metal structures on fire. We also studied the effect of the number of bolts on the stresses and transitions in the link and their comparison with the welding cases. We studied and analyzed the studied model and obtained the deformation and failure schemes at high temperatures, the flow charts and the temperatures that show the behavior of this link to the fire. We also obtained the stress and strain schemes for the link and the transport and load schemes at different temperatures and the behavior of this link at these different temperature.