A　variety　of　synthesis　parameters　for　the　preparation　of　gold　nanoparticles　by　NaBH4　solution　reduction　in　the　W/O　microemulsion　media　consisting　of　Cetyl　Trimethyl　Ammonium　Bromide　(CTAB)/n-hexanol/water　system　was　investigated.　The　results　showed　that　the　molar　ratio　of　water　to　surfactant　(r(w))　had　nothing　to　do　with　the　gold　particle　size,　but　the　concentration　of　the　aqueous　gold　salt　solution　had　a　significant　effect　on　the　size　of　gold　particle.　Through　optimizing　the　preparation　parameters,　Au/Al2O3　catalysts　were　prepared　with　two　different　methods,　then　the　catalysts　were　characterized　by　ultraviolet-visible　spectra,　XRD　and　TEM,　and　the　effect　of　two　different　preparation　methods　on　active　component　gold　particle　size　in　the　catalysts　was　studied.