The macromolecules considered for the study were fetched from RCBS Protein Data Bank (PDB: ). The macromolecules namely 1EVE THREE-DIMENSIONAL STRUCTURE OF THE ANTI-ALZHEIMER DRUG, E2020 (ARICEPT), COMPLEXED WITH ITS TARGET ACETYLCHOLINESTER ASE modeled using Autodock 4.0. The crystal structure contains water all the water molecules are removed, the hates are deleted and the missing hydrogens are added, additional Kollman united atom charges were assigned and Partial atomic charges of all the atoms were calculated using the Gasteiger -Marsili method. have been added, and added and the hate atoms and chains which are don't present at drug (E2020) and drug pocket or active site are deleted. The grid was generated around the E2020 ligand the grid file output used in MGL Tools 1.5.7 (The Scripps Research Institute, Molecular Graphics Laboratory, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA. The output grid file and Autodock vina were used for the calculation of the target site and ligand binding energy.