FAIR principle is the guiding principle for regulating scientific data management and promoting data sharing. Investigating and analyzing the current practice status of FAIR principle in China's National Science Data Center is of great significance to facilitate the discovery, exchange, acquisition and reuse of scientific data. This article grasps the international principle of sharing scientific data by analyzing the main contents of FAIR principle; investigates the current practice status of FAIR principle in 20 National Science Data Centers, analyzes the results from two levels of metadata standards and user authorization and proposes improvement suggestions. It is found that the application of FAIR principle in China's National Science Data Centers still needs to be improved, and standardization management should be strengthened in terms of the adoption of persistent identifiers, the open access of metadata standards and the clarification of data permission statements.