Abstract: Open & shared data is an essential facility for incubating data single market. The frequent emergence of data monopolistic behaviors makes data run separately, which seriously undermines the order of data competition and hinders the cultivation of data single market. Germany and the EU have legislated for essential data. However, the essential facility doctrine, which originated in the industrial economy, cannot be applied to data directly in the digital economy. Some dilemmas still exist in judicial practice, such as the wide variation in the selection of applicable criteria, the unclear scope of essential data, and the potential multiple risks of data sharing. The application of essential data should be optimized in three aspects. Firstly, the positive and negative conditions for the application of essential data should be standardized; secondly, it should distinguish the different meanings of data resource or data assets in the antitrust law, and set the scope of essential data in regulations; finally, in terms of the feasibility of data sharing, a secure & reliable data sharing method, and a dynamic & integrated data pricing mechanism should be established.