Abstract: For the process modeling of complex product, a methodology of an iterative question driven simulation process is introduced. In which, the design process model is capable to describe problem statements, model specifications, simulation models and problem answers as separate objects. This enables a granularity level of information that allows traceability on an object-to-object level between the attributes in the requirements specification and the estimated product properties. This also offers a traceability and reuse of partial result created during the verification of a specific requirements attribute as well as a possibility to study the effects that changes in the requirements specification have on product properties. A methodology for an iterative question driven simulation process using this design process model has been illustrated in a modeling and simulation scenario of a working unit in a large hydraulic excavators from Taiyuan Heavy Industry Co.,Ltd. Based on an iterative question-answer driven process, the best design plan of hinge points is chosen from 5120 different attachment hinge points’ designs and the traceability from the establishment of the requirement specification to the draft process of the decision basis is realized. It showed that the question-answer driven method is a valid method, could meet the design requirement.