Abstract Because of its rare and stable nature, gold has long been used as jewelry, currency and financial reserves, and therefore has not been applied in the chemical field. However, when gold is dispersed into nanoscale particles, it has many special physical, chemical and biological characteristics because of its surface effect and small size effect. The preparation and characteristics of gold nanoparticles are introduced. The applications of gold nanoparticles in disease screening and diagnosis, DNA recognition and detection, food safety detection, efficient and green catalysis are reviewed from the perspective of technical principles, including immunology, biochemistry, catalytic chemistry and other fields.