Polysiloxane/SiO₂ hybrid coatings have been prepared on Kapton films by a sol-gel process. The erosion resistance of polysiloxane/SiO₂ (20 wt pct) coating was evaluated by exposure tests of vacuum ultraviolet radiation (VUV) and atomic oxygen beam (AO) in a ground-based simulation facility. The experimental results indicate that this coating exhibits better AO resistance than pure polysiloxane coating. The erosion yield (Ey) of the polysiloxane/SiO₂ (20 wt pct) hybrid coating is about 10¡27 cm³/atom, being one or two orders of magnitude lower than that of polysiloxane. VUV radiation can affect the erosion process greatly. Under simultaneous AO and VUV exposure, the value of Ey of the polysiloxane/SiO₂ (20 wt pct) hybrid coating increases by 39% compared with that under single AO exposure.