In the era of digital transformation, data elements have become the core engine for the in-depth development of the digital economy.The value realization of data elements depends on circulation and utilization, and data trading is the main means to promote data circulation and improve data utilization efficiency.In order to adapt to the current trend of marketization and centralization of data trading, data trading platforms represented by data exchanges have rapidly emerged and developed.However, at present, there is a lack of a support system and standards for data exchanges in China, and the governance framework for data exchange is still in a vacuum.Previous research findings have provided useful references for institutional norms in data exchange, but in essence, they have not separated from a single research perspective on the internal mechanisms of data exchange, and are mostly embedded in the research results of data transactions, without targeted analysis of institutional norms.#br#The study employs the historical institutionalism analysis method, comparative analysis method, induction and summary method to explore the policy changes, functional orientation and norm configuration of data exchanges in China.First of all, it reviews the historical picture of data exchange policy changes in China.According to the policy supply of data exchanges and the number of institutions established, this study divides the historical changes of China's data exchanges into three stages: the first development period spanned from 2014 to 2017, followed by the cooling-off period of the data exchange from 2017 to 2020, and the third development period began in 2020.From the perspective of historical institutionalism, national macro-systems related to information technology affect changes in data exchange policies.The institutional decision-making bodies of data exchanges are evolving in a delayed direction, and the mutual relationship between norm makers is also strengthened.The transformation of data exchange policies and norms, as well as the policy norms of China's data exchanges, are based on the deepening needs of the country and the public.#br#Second, this study analyzes the unique attributes of data exchanges from a comparative perspective.By comparing data exchanges with stock exchanges, it is concluded that the internal governance rules of data exchanges should follow the principle of 'object heterogeneity' in data transactions, pay attention to the attribute of 'bundle of rights' of data elements, and integrate the external industry standards of data into the certification mechanism of data exchanges.After comparing data exchanges with data sharing platforms and data service providers, it is stressed that the system configuration of data exchanges should pay more attention to the code of conduct before and during transactions, and its main function is to alleviate the information asymmetry between buyers and sellers of data, and build an interactive trust mechanism based on the information disclosure system.In addition, the norms should legally confirm the independent subject status of the data exchange, guarantee the basic rights of self-discipline management of the data exchange, and standardize the supervision, management and punishment power of the data exchange to members, brokers and other subjects.The governance norms of data exchanges also need to pay attention to the companies′ internal governance structures and procedural norms to prevent any possible moral hazards of the shareholders, board of directors and senior managers.#br#Finally, on the basis of the aforementioned policy evolution and comparative analysis, this paper proposes a guaranteed mechanism for data exchanges.The legal norms should uniformly position the legal subject status of the data exchange as a public welfare corporate legal person performing self-regulatory functions and provide guiding normative content about corporate governance.Laws and regulations should also specify the functions of shareholders, directors, supervisors, and senior managers of data exchange companies.In terms of data transaction mechanism, it is necessary to establish a complete trading qualification recognition mechanism, provide accurate pricing mechanisms for data products, and address gaps in information disclosure mechanisms.For external governance, China should establish a multi-layered collaborative regulatory framework of 'central-local-industry organization' for the legal protection mechanism of the data exchanges, incorporate diversified governance subjects, enhance social governance capabilities, and focus on resolving governance difficulties from local competition.#br#