Diamine-decorated graphene oxide (NH2-GO) is successfully synthesized by covalently intercalated ethanediamines into the flat planes and edge of the GO sheet. The diamines could be act as buffer layer, thereby avoiding the stacking of graphene sheets, and offer abundant metal-chelating sites to subsequently obtain well-dispersed metal nanoparticles of small size. After the in situ reduction and deposition of AuNPs, it was found that the Au particle size of Au-0.9%@NH2-GO estimated to be around 2-5 nm. The as-prepared GO-supported small AuNPs exhibited good catalytic performance for the heterogeneous epoxidation of alkenes with H2O2 under mild conditions. Notably, they presented good expansibility for either bulky or less bulky alkenes in this reaction, owing to the facilitated efficiency of mass transfer of substrates and products resulted from the supporting effect of intercalated diamines and high surface area of GO. Moreover, these heterogeneous catalysts could be readily recovered and recycled for five times with the remained activity and selectivity. Graphic Gold nanoparticles of small size immobilized on the diamine-decorated graphene oxide has been developed, which employed as an efficient, universal and reusable catalyst for the epoxidation of alkenes using H2O2 as an oxidant.