The environment confronting modern organizations possesses high uncertainty arisen from ever-increasing complexity, competitiveness and dynamics, which make organizational characteristics including organizational structure to be experiencing great alteration so as to suit the environment. The kernel of organizational management is decision, and the process of decision-making is just the one of information processing. In this paper, as an emphasis, the problem of organizational structure design under uncertain environment was studied from the angles of organizational decision—making and information communication．A model of organizational decision eonsidering uncertain environment was set up．On the basis of the model，the concept of organizational structure value was introduced．Integrating qualitative and quantitatire method s derived a mathematieal expression reflecting their relations among organizational environment organizational decision and organizational structure．According to the expression，some conclusions meaningful to organizational structure design under uncertain environment were obtained． The study shows that，under the environment of uncertainty，organizational structure should keep high flexible for the purpose of improving decision effectiveness；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 whole communication channels are rigid and restricted．However a specific organizational structure design should depend on varied kinds of factots．Such factors along with their influences on organizational structure design were investigated as wel1．