We achieved a highly efficient one-pot synthesis of permethylated alpha-cyclodextrin(CD)-based polyrotaxane via an initial complexation to the inclusion complex with amine-terminated polytetrahydrofuran followed by end-capping with it bulky isocyanate in hydrocarbon solvent under heterogeneous conditions. Among various organic solvents tested, isooctane was the best solvent, while cyclohexane yielded no polyrotaxane. Effects of the reaction temperature, the molecular weight of the axle polymer, file structures of file wheel and axle components oil the yield and coverage ratio of the polyrotaxane were studied in detail. Under the optimum conditions, we obtained a 71% yield of polyrotaxane with it 67% coverage ratio when amine-terminated poly(tetrahydrofuran)(M-n 8700) reacted with permethylated alpha-cyclodextrin at 50 degrees C in a isooctane . We discuss the reason for and the mechanism of the efficient reaction that occurred in the heterogeneous system from the viewpoint of the role of the solvent and the results of the solvent-free synthesis previously reported. By a similar one-pot reaction, polyrotaxane consisting of permethylated alpha-cyclodextrin and poly(ethylene glycol) was first synthesized. Neither native alpha-CD nor permethylated beta-CD gave any polyrotaxanes when amine-terminated poly(tetrahydrofuran) Was used its all axle polymer.