Functionalization of polyethylene chains by grafting of polar groups onto backbones is the most versatile way for preparing polyethylene based compatibilizers (PECs). In this work, a series of theoretical studies were performed to analyze the structure, adhesion and mixing behaviors of PECs. The effect of grafting different polar groups such as acrylic acid (AA), glycidyl methacrylate (GMA), maleic anhydride (MAH) and itaconic acid (IA) on the structure and cohesive properties of polyethylene chains were studied by Molecular Dynamics simulations. The mixing behavior of grafted polyethylenes with some commodity polymers such as polyetylene teraphthalate (PET), polyamide 6 (Nylon6), polyvinyl acetate (PVA) and polylactide (PLA) as well as with starch (ST) and starch acetate (STac) were investigated quantitatively by determining accurate interaction parameters using the modified Flory-Huggins Theory. We showed that the polar groups are the most reactive sites and they bind the chemically incompatible polymers by enabling the stronger interactions at the interfacial region.