Abstract: Based on the rule of task,a novel task-based access control （TBAC） model was proposed to improve the permission administration and mechanism in the conventional TBAC model by the definitions of task-permission set alone.The permission constraints focus both on the task and permission,and some formal analyses and some constraints rules for permission set are presented.The proposed model was applied to the Aerospace Vehicle Collaborative Development Management system AVIDM.Experimental results show that the model could provide a more agile authorization and enhance the practicability of task model.Moreover,it simplifies the task complexity of permission administration.It is well suited to the access control in transaction management system and workflow system.