Abstract: Gold nanoclusters (AuNCs) are gold atom aggregates less than 2 nm (excluding the ligand shell) or 150 atoms. It has been widely studied due to its small size effect, fluorescence property, and catalytic activity. In this review, research progress in the preparation of gold nanoclusters containing accurate atom numbers using biomolecules and chemically synthesized molecules as ligands have been summarized. The factors that affect the preparation of gold nanoclusters have been discussed. The applications of AuNCs having accurate atomic numbers in the fields of analyte assay, catalysis, bioimaging, and drug delivery have been introduced. This review provides references to the further researches on the preparation technology and biomedical applications of AuNCs.