Soluble copolyurethaneimides were synthesized by the isocyanate method in a solution of N-methyl-2-pyrrolidone (NMP). The isocyanate-terminated prepolyurethane prepared from low molecular weight polyethylene glycol) (PEG) or polypropylene glycol) (PPG) and methylene diisocyanate was reacted with pyromellitic dianhydride at high temperature. The resulting copolyurethaneimides were soluble in polar solvents like N-methyl-2-pyrrolidone and N,N'-dimethylformamide. The film-forming properties were investigated by changing the molecular weights of PEG and PPG. With PPG, the film-forming property was enhanced. The inherent viscosity, solubility, thermal property, molecular weight distribution, and mechanical property were compared with the aromatic polyimide.