Gold nanoclusters are composed of several to a hundred atoms. As a kind of fluorescent materials, gold nanoclusters have recently attracted significant attention because they provide the link between atom and nanoparticle. Gold nanoclusters exhibit unique optical properties due to quantum effect as their sizes are close to the Femi wavelength of electrons. Fluorescent gold nanoclusters have attractive characteristics such as small size, good water solubility, remarkable photophysical properties, large surface area, and facile surface modification. Recently, a variety of synthesis approaches for the preparation of water-soluble fluorescent gold nanoclusters have been developed, which significantly facilitate the understanding of their properties and applications. It has been proven that the fluorescent properties of gold nanoclusters could be adjustable by using suitable ligands and biocompatible scaffolds. Until now, fluorescence gold nanoclusters have shown potential applications in the fields of biosensors, nano-labeling, molecular imaging and optoelectronics. As a novel class of fluorescent probe, fluorescent gold nanoclusters have been used for the sensing of small molecules. In this review, we highlight the recent advances in fluorescene determination of metal ions, anions, and the biological organic molecules including hydrogen peroxide, glucose, glutathione, adenosine triphosphate, and amino acids. The current challenges and future perspectives in this research area are also outlined.