Abstract: Directed towards the characteristics of uncertain environment the modern organization faces, a general mathematical model of organizational decision-making is established. The organizational structure and its value are investigated in the views of decision-making and information communication. Integrating qualitative and quantitative methods, the quantitative expression of the organizational structure value is derived. The influence of organizational structure on organizational decision-making is analyzed, while some conclusions meaningful to organizational structure design are obtained. The study shows that, in the environment of uncertainty, the more information sharing among decision units enables organization to make the better decision, and the network organization whose communication channels are flexible and open has advantage over the hierarchical organization whose communication channels are rigid and restricted.