The co-coated HMX particles and burning-rate catalysts by emulsion polymerization of OH-terminated PU prepolymer and isophorone diisocyanate was studied. During preparation of OH-terminated PU prepolymer, tris-(hydroxy methyl) propane was chosen as triol monomer to improve the abrasion resistance and solvent resistance of the final crosslinked coatings. The experimental results show that the burning-rate pressure exponent of NEPE propellant thereof decreases 0.04 by using co-coated HMX and burning-rate catalyst. An applicable coating procedure is also given herein.