The emulsion of methyl methacrylate-methacrylic acid copolymer [P(MMA-co-MAA)] was modified by nano-silica (SiO2). The structure and properties of the composite emulsion were determined by infrared spectroscopy (FTIR), thermogravimetry (TG), X - ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the aggregation structure ofP(MMA-co-MAA) has been changed after the addition of nano-SiO2, resulting in the change of self-embritting morphology of the emulsion. The main performance is that, with the increase of nano-silica content, crisps have a big trend and shrinkage is more obvious, which promotes the self-embrittlement and stripping performance of P(MMA-co-MAA). This performance has the advantage of removing radioactive waste from the surface of the equipment.