Abstract: The new steel section known as triangular web profile (TriWP) was studied by previous researcher to replaced flat web (FW) steel section for better resistance on bending behaviour. In order to reduce the weight of TriWP steel section for economic purposes opening on the web steel section is introduced. This paper described the study on the bending behaviour in major axis and mainly focus on the effect of opening on the TriWP, effect of the web thickness on triangular web profile with opening (TriWP with opening) steel section and effect of different type of opening shape on TriWP with opening. The TriWP with opening steel section with 200×100×6×3 mm size was analyze using finite element analysis. From finite element analysis it can be observed that the deflection on TriWP steel section is less compared to that TriWP with opening steel section. The different of deflection between TriWP with opening steel section and TriWP steel section is less than 1 mm. The deflection of the section based on manual calculation is 1.292 mm which is less than 8.33 mm, deflection limit of the section. Therefore TriWP with opening can resist and carry the same load as TriWP steel section can carry.