||The key objective is to inhibit the replication of HTLV through developing a potent and effective compound targeting HTLV-PR enzyme, by understanding the binding level atom interactions and charge environment present in both ligand and surface of active site of HTLV-PR. The proper identification of binding site features, complementary lead design which appropriately fits to receptor binding environment is essential for high binding affinity through the free energy calculations. FEP calculation are more accurate calculations, thus we are planned to design compounds based on active site requirement and obtain the free energy values. FEP calculation on ligand functional group changes informs the chemical entity, which can enhance the ligand designing. Combined planning of interaction studies, energetic calculation, Quantum mechanics will brought up the inhibitory action towards the HTLV-PR and new novel compounds for T-Cell lymphotropic virus (Anticancer drug design).