Abstract: For the generation of manufacturing planning(MP) in mass customization,information modeling for tiered activities in CAPP is studied.Based on systematic information modeling,information,activities,and its relationship in manufacturing planning are analyzed.Object-oriented systems analysis(OSA) approach is made use of to describe the static and dynamic characteristics of information involved in manufacturing planning.Thereby,the correlative relationships within the MP between part design and manufacturing planning can be properly described.A tri-level decision-making mechanism is employed to formularize the manufacturing planning model.Thus computer aided manufacturing planning(CAMP) under certain manufacturing resources are realized.Finally a case study of manufacturing planning is presented to verify the feasibility of the method.