Using 5% multibenzylalkyl multiisocyanate acetone solution as surface-treating reagent,the surface of single-base gun propellant was treated synthetically by chemical and physical methods. The effect of this method on burning performance of single-base gun propellant was studied by constant-volume burning experiment. Results show that the burning performance of single-base gun propellant changes obviously after surface treatment by multibenzylalkyl multiisocyanate. The burning-gas releasing brisance and activity have increased at burning metaphase and anaphase,and which contributes to enhancing energy availability of gun propellant. The burning-gas releasing laws of surface-treated gun propellant accords with the needs of interior ballistics much better. The appropriate thickness of surface-treated layer of this method is about 45 μm,and the effects of controlling burning performances of gun propellant will be depressed by over many surface-treating.