Abstract: The present invention discloses a process for forming a solution containing gold nanoclusters binding with ligands, the process comprises the following steps: provide a aqueous solution that comprises a gold precursor, a base and ligands; perform a reduction reaction by adding a reductant into the aqueous solution to form a liquid containing gold nanoclusters binding with the ligands; concentrate the liquid containing the gold nanoclusters binding with the ligands to a solid; dissolve the solid into water to form a crude solution; and perform a purification process by passing the crude solution through a membrane or a dialysis tube to obtain the solution containing the gold nanoclusters binding with the ligands.