Gold nanoparticles,also known as colloidal gold,have the characteristics of colloid,is a kind of suspend liquid containing gold particles reduced from gold salt.In this paper,several methods of making gold nanoparticles,such as microwave technique,UV irradiation,electrochemical method,template method,and so on,are mainly introduced.The application and prospect of colloidal gold in the fields of the catalyst,biochemical analysis,sensor and other fields according to the different characters are also reviewed.