Change in pH plays crucial role in stability and function of dengue envelope (DENV) protein during conformational transition from dimeric pre-fusion state) to trimeric form (post-fusion state). In the present study we have performed various molecular dynamics (MD) simulations of trimeric DENV protein at different pH and ionic concentrations. We have used total binding energy to justify the stability of complex using MMPBSA method. We found a remarkable increase in stability of complex at neutral pH (pH~7) due to the increment of sodium ions. However, at very low pH (pH~4), total energy of the complex becomes high enough to destabilize the complex. At a specific pH, almost at range of 6, the stability of the complex is significantly better than stability of trimer at neutral pH, which connotes that trimer is most stable at this pH (pH ~6).