Abstract: The completion risk problem for a project is studied under the constraints of project investment and precedence of subprojects in the case where the owner and partners in a virtual enterprise (VE) have asymetric information. In view of how each subproject's completion time is affected by allocated cost from the owner, and by the distribution feature of decision-making in VE, a novel cost-time based completion risk management framework by negotiation is proposed to meet completion probability requirements and control project risk. At the same time, three concession tactics are designed. The framework has two levels： the top-level owner, and the base-level partners. The partners determine the three-estimate times based on allocated cost from the owner, and then feed them back to the owner. After receiving partners' responses, the owner evaluates them based on program evaluation and review technique (PERT). Finally, a numerical example is studied under these three tactics, and the results show that this framework can achieve effective completion risk management.