A series of polyethylene-g-polyfluorosiloxane (PE-g-PMTFPS) copolymers with well-defined microstructures were synthesized via the combination of hydrosilylation, anionic ring-opening polymerization, and coordination copolymerization. To establish a database for the controllable synthesis of these graft copolymers with specific microstructures, groups of copolymerization reactions were carried out by varying reaction conditions. The incorporation of PMTFPS macromonomers into resulting copolymers increased proportionally with the increasing initial feed of PMTFPS macromonomers, while PE backbone length decreased. The variation of molecular weights of PMTFPS macromonomers allowed the direct regulation of PMTFPS side chain length. Meanwhile, both branch density and PE backbone length decreased with the increasing macromonomer molecular weights. The decrease in reaction temperature led to the decreasing incorporation of PMTFPS macromonomers, but PE backbone length increased considerably. These influencing factors could effectively adjust the branch density, branch length, and copolymer backbone length, which afforded the tailor-made fabrication of PE-g-PMTFPS graft copolymers with desired microstructure.