The design of structural modeling is usually based on the different geometric function. Since every component has a definite life span, it is necessary to calculate its core parameters. To find the life span of component, the component must be as input parameter to the Finite Element Analysis. The Finite Element Analysis is nothing but a numerical method for solving Engineering and Mathematical problems. The Analysis of the “Rear Axle Casing of Tractor” using cast iron material with special grade “SG 500” for already existing model, taken in the real time is done by using “ANSYS”. The stress, strain, deformation analysis of the component is done by giving various boundary conditions. These analyzed results help to redesign the rear casing of tractor. The redesigning of rear axel casing of tractor is done using “PRO/E”. During redesigning the component, various criteria’s taken in the real field must be taken into an account. The analysis of the redesigned model is done by giving various boundary conditions for both materials ‘SG 500” and “SG 200”. Then the stress, strain, deformation, structural supports, structural results are evaluated and also cores, dies and patterns are generated and hence the redesigned rear axel casing of tractor is found to be in safer mode. And also the better material for the rear axle casing is given, by comparing the above mentioned materials.