The aim of this study was to investigate temperature distribution and thermal stress analysis of isotropic rectangular plate due to convection by dissipation. The convection heat is applied in the form of partial distribution which is represented by Heaviside unit step function. The finite element formulation has been developed to solve governing heat conduction equation which results the rate of heat transfer and temperature distribution within rectangular plate. Also the classical theory of thermo elasticity has been used to develop the finite element formulation for thermo elastic stress analysis. The results of temperature and stress have been computed numerically, illustrated graphically and interpreted technically.