A new cellulose graft copolymer was synthesized by the homogeneous graft polymerization in ionic liquid. The methyl methacrylate was successfully grafted onto the bagasse cellulose in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) as a homogenous media. The obtained copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscope (SEM). The results of thermal analysis curves exhibited two separated pyrolysis with cellulose and the grafted pMMA. Moreover, the homogenous reaction media applied can be carried out in completely recycled ionic liquid, and the modified cellulose has a potential value for oil absorbent.