Prototype of a Knowledge-Based Program System for System Simulation. The present article describes a new approach for merging numeric simulation techniques and knowledge-based methods for process simulation. In a first step the potential of such a combined technology is outlined, concerning both knowledge-based user support in handling and application of simulation codes as well as the support of the engineering task for chemical process development. An analysis of implementation techniques outlines, how an adequate integration of numeric and knowledge-based software modules can be achieved by adoption of the object oriented programming paradigm. The resulting requirements for the modelling of knowledge and the corresponding inference mechanisms are explained and a software prototype is presented by which this knowledge-based simulation technology is currently being evaluated and refined using a case study from aerospace domain.