A durative project risk management mechanism of inter-organizational collaboration is presented. At the period of risk factors’ identification, an identification method based on characteristic-factor modeling technology, checklist and flow chart is put forward. In the period of risk quantificational management, a sort of realization method is described as following, at first, the single risk quantification can be handled by the comprehensive fuzzy evaluation method; secondly, the whole risk quantification can be handled by the improved PERT （Program Evaluation and Review Techniques） method. In the period of risk response, a response method on the basis of ANN （Artificial Neural Networks） and frame knowledge expression and reasoning is put forward, and a mixed expert system which can make the risk response intelligent is built up. Results indicate that the method of risk management is feasible.