In this work, micrometer-sized flower-like Au particles (Au microflowers, Au MFs) can form on the poly(N-isopropylacrylamide) brushes-grafted-graphene oxide (PNIPAM-g-GO) film via a spontaneous redox reaction. The "swelling-deswelling" behavior of the thermoresponsive PNIPAM brushes at different temperature could tune the morphology of Au MFs. The as-prepared PNIPAM-g-GO/Au MFs composites exhibited excellent surface-enhanced Raman spectroscopy (SERS) performance and the enhancement factor was estimated to be about 10(5) for 4-aminothiophenol.