Nano-sized gold particles dispersed in a composite were prepared by using NH2-terminated polyethyleneoxide (PEO-NH2) as a matrix. Gold was vapor-deposited onto a melt of PEG-NH2. Gold was smoothly dispersed into the interior of PEG-NH2 to form nano-sized gold particles. After cooling the melt to room temperature, a stable solid composite was obtained. The composite readily dissolved in water or various kinds of organic solvents to produce a stable colloidal solution. The mean size of the gold particles was 3.4 mn, and the content of gold was ca. 5 wt%.