Depending on the nature of the actual physical system and the purpose of the simulation, the definitions of modeling and simulation will vary. Simulation is a technique that involves setting up a model of a real simulation and performing experiments on the model. This paper deals with simulating and modeling electromagnetic fields in Macsyma environment. Computers have traditionally been used to solve scientific problems that could be expressed in terms of numbers. The programming languages FORTRAN, C, C++ or JAVA assist scientists in dealing with numeric problems. This approach to problem solving works well, when a problem can easily expressed in terms of calculations with numbers. But there are some problems which can be expressed best in symbolic terms, or can only be expressed that way. Such solutions are very useful for interpretation of results. In this work; Maxwell's equations, Laplace equations, Wave equations, and Rectangular waveguides will be examined in several coordinate systems.