This work pursues a new approach for the modeling of micro mechanics in systems of the micro system technology: The modeling bases on a building block set of models for basic effects. The model equations of the effects are based on analytic equations, which need little computing time and thus suitable for system simulations. The models were implemented in an analog hardware description language (VHDL-AMS, IEEE standard 1076.1). This supports the co-simulation of electronics and mechanics, and thus the simulation of complete micro systems in circuit simulators. For the automatic design of the layout of silicon-based micro mechanical structures a layout generator was created, which is based on a commercially available GDS-II library. A synthesis tool with integrated user interface provides the necessary data for the coherent layout generation and model conception on basis of functional values. This supports the design of micro-electromechanical systems (MEMS) with the top-down method. The method is illustrated on the basis of micro mechanical demonstrators: a pressure sensor system, a gyroscope, an accelerometer and a micro mirror system.