The authros developed a new approach to preparing the Au@SiO2 core-shell nanostructure. The morphology and stability of the composite were characterized by the UV-Vis absorption spectroscopy and transmission electron microscopy (TEM) methods. The stable SERS spectra were obtained from the PMBA-functionalized Au@SiO2 composite. In addition, the authros succeeded in adjusting the thickness of SiO2 layer by controlling the precursor consumption. The stability of Au@SiO2 in basic solution was studied and the results showed that the SiO2 shell was facile to be etched. The present work may provide a reference and gist for research on the preparation, storage and application of Au@SiO2.