The convergence of the representation based methods used in artificial intelligence and simulation has originated the emergence of Knowledge-Based Simulation. The objective of this new approach is to achieve more powerful and understandable simulations, which will allow the simulation developers to construct, validate, develop and maintain simulations that can model a wider range of complex systems, and which will allow the users to interact with the simulation in nl-der to achieve a greater comprehension of the modeling phenomenon. In this work there is a definition of the possible contributions that the expert systems can give to the different life cycle stages of the discrete events simulation. Specifically, we propose nn example of a discrete events system, in particular about a waiting phenomenon, and consequently constructing production rules to be applied in: the model development, The parameters estimation,and the results analysis and interpretation..