The present work is a computational approach which predicts about some potential HIV protease inhibitors that acts as anti dengue drugs by inhibiting NS3 protease of Dengue virus. In order to study the activity of these selected potential drug molecules, taking two best docked complexes Molecular Dynamic Simulation was performed considering water as solvent and at 1 nanosecond time scale to investigate the structure, dynamics, thermodynamics and stability of the complex in the targeted environment. Further pharmacophore modelling and finally QSAR analysis was performed by taking some of the photochemical and structural descriptors. The effect was calculated for each type of descriptors by taking Andrews affinity as a dependent variable. The results obtained with these models suggest, for this particular drug molecule photochemical descriptors play a major role in controlling the activity which is consistent with the result obtained from filmmaker modelling.