Coatings can be roughly divided into liquid coatings,powder coatings and dry coatings.For each type of coating,the density is a very important index.For the density of liquid coating,there are five test methods,such as specific gravity cup method,immersed body method,oscillation method,pressure cup method and areometer method.For powder coating density,the test methods include gas replacement method and liquid replacement method.For dry coating density,the test methods include using a coated test panel to determine dry flm density by the Archimedes principle and to determine directly by Archimedes principle.In this paper,the characteristics,accuracy and application status of each test method were explained in detail.