Abstract: The building of a large unified national market is the basic support for realizing the new development pattern. In the era of digital economy, platform enterprises, as key market players under the digital economy system, effectively plays a leading role in consumption, education, medicare and other activities through a comprehensive digital transformation. Based on Internet technology, the connectivity of platform enterprises strengthens their network externalities, multiple attributes of bilateral users of the platform, and the value creation effect of the dual identities of platform enterprises, thus effectively promoting the construction of a national unified large market by improving the unity, openness, competitiveness and orderliness of the market. However, the obstacles existing in the process of promoting the operation of interconnection and the potential obstacles caused by interconnection restrict the process of building a unified big market. To this end, a series of policy suggestions are put forward from the aspects of enhancing platform enterprises awareness of connectivity, strengthening connectivity technology research and development, strengthening the construction of data protection measures, strengthening the construction of anti-monopoly system of connectivity, etc., so as to standardize the platform economy development and promote the big unified national market construction.