High molecular weight poly-hydroxy-terminated glycidyl azide polymer (HGAP) is a new type of energetic polyether binder for the development of high performance solid propellants. The preparation of HGAP from degradation of polyepichlorohydrin (PECH) and azidation is described and the said polymer with M_n 1500～20000, f_n 3～6, and molecular weight distribution about 2, was prepared by tailoring different factors.