The polyimide-silica-silver hybrid membranes supported on SiO2／K-M were prepared by sol-gel route and characterized by means of IR

TGA

SEM

XRD

N2 adsor ption and gas permeability measurements．The results show that the viscosity of hybrid sols and the pore size of bybrid membranes are increased and the pore size distribution is disporsed bv the addition of silver nitrate．Silica and silver existed as amorphism and silver chloride in hybrid membranes

respectively．Silver is bonded with nitrogen in polyimide and propylene is adsorbed on silver by double bond．The thermal decomposing temperature of hybrid membranes is increased by addition of silica and reduced with increaseof silver amount．The separationfactorsof propylene/pmpanethroughthe hybrid membrane are 3.54～4.1.The obvious facilitated transport of pmpylene is realized by the addition of silver．