In the era of digital economy, the data has increasingly become one important production factor. Taking Guiyang Global Big Data Exchange (GBDEx) as an empirical case, this paper first proposes a SEED model for constructing the data factor market which mainly consists of four components: S for System rules designing which refers to the design of rules, standards, policies and laws on data transaction process; E for Exchange platform building which should be credible, controllable, reliable and traceable; E for Ecosystem nurturing that refer to diverse data suppliers, customers for data demand, data intermediaries, data regulators, and other data trading alliances should be nurtured; and D for Data convergence and co-governance refers to the convergence and co-governance of various types of data trading subjects. The SEED can also be interpreted as a process of constructing the data factor market, with the data exchange as the core, igniting the vitality of the whole data factor market like a seed. We believe this paper can make contributions to the digital economy literature: first, it contributes to extant literature on data marketplaces and data ecosystem; second, it provides practical suggestions for constructing the data factor market; third, relevant policy makers and higher-level managers will likely achieve much enlightenment from this paper.