The study of effect of torsional parameter on steel beam section is studied. The paper aims at studying the strength and deflection pattern of I section steel beams for varying torsional parameter for combined bending and torsion under various loadings, support conditions. The comparative analysis for beams with varying geometry of symmetric and un-symmetric I sections subjected to concentric and eccentric point loads and torsional moment with simply supported, cantilever and fixed end conditions is presented using finite element analysis ANSYS 18.1 workbench. Two different types of sections were selected for both symmetric and un-symmetric I beams with lengths of 4 m. It was seen that the ANSYS software resulted in much easier modelling, faster and cost-effective analysis for the thin-walled steel beam sections. The maximum transverse and axial deflection, the equivalent maximum stresses and strains of beams were studied along with the influence of bending and torsion for varying torsional properties of the adopted sections. It was observed that greater value of transverse deflections, stresses and strains were obtained in case of beams with higher value of torsional parameter with cantilever support condition but lower axial deflections. Lesser values of stresses and strains were obtained in the un-symmetrical I sections than the symmetrical sections for flexural effects.