Abstract: Data circulation is a novel and important means to facilitate productivity. Different from the trade of normal products, the requesting, addressing, answering and transmitting of data involve complicated procedure, and a single requirement may lead to multiple answers or even bids. Accordingly, a fundamental issue in building up an efficient and effective system for data circulation is to design a credit allocation mechanism. This paper analyzes the typical pattern of data demand and data supply, proposes an incentive network model containing requesting node, intermediary nodes and answering nodes, and designs a geometrical decaying mechanism in credit allocation. Under the above general framework, we show some typical models and the corresponding calculation processes, and extend the single chain model to the general situation involving multiple answering nodes with different weights. Lastly, we discuss how to deal with more complicated cases under this framework, such as allowing bids in competition of multiple nodes.