With the development and widespread application of the new generation of information technology，data is playing an ever increasingly important role in value creation and has become an important production factor in the era of digital economy. The flow of production factors along the production line is not only a process of value creation，but also a process of data flow. Therefore，the traditional value chain is extended to the data value chain. This paper argues that data value chain is a process of data flow and value creation along the production chain of an enterprise，which presents，in comparison with traditional value chain，a series of different characteristics. This paper reveals economic characteristics of data production factor，basic functions of data and value creation mechanism，and analyzes the value creation role of data in the main parts of the value chain such as research and development，manufacturing，marketing，and services. The value creation of the data value chain is affected by data granularity，freshness，connectivity，feedback，responsiveness，and processing. This paper finally proposes policy recommendations for the government regarding promotion of the development of data value chain as well as enhanced function of data value creation.