Abstract. The aim of this study is to design a computation program of thermal distribution by using the Line Successive Overrelaxation (LSOR) method through the finite difference approach in the language of MATLAB (Matrix Laboratory). The methodology used in this study is a literature study. The result of this study is a computation program that can perform appropriately to show the thermal distribution of a two-dimension system in a steady state. The output of the program is visualized by MATLAB in a contour graphic and a two-dimension graphic. Key words: Computation, thermal distribution, Line Successive Overrelaxation (LSOR), finite difference, MATLAB