Abstract:There are various risk resources of accident in space-limited project, and easily cause relative chain reactions. It is significant for risk management of space-limited project to rapidly identify risk sources and effectively get assessment of the risk of each induced accident node. Authors identify risk sources of space-limited project and construct a Bayesian Network risk model to get the posterior probability of each risk source node which uses Bayesian Network’s forward prediction and backward diagnosis. Then authors calculate the mutual information of probability of risk source and accident, introduce a concept of controllable and quantified value of risk sources to construct Twodimensional & Four-zones (TDFZ) risk management model based on mutual information, and propose corresponding management strategies. Finally, authors explain the research result through an example.