This thesis explores achieving hierarchical supervision with nonblocking by a practical computational method. We provide a feasible approach to establishing a certain property, named hierarchical consistency with marking, for the pair of low and high-level DES making up a two-level hierarchy. In order to complete the hierarchical control loop, we provide feasible procedures to implement the inverse reporter map and thus to model the command channel from the high level to the low level. For the implementation of our algorithms, software has been developed which can serve as a computational tool for analysis and design. Finally examples are presented to illustrate the performance of our computational method in practice.In the control of discrete-event systems (DES), hierarchical supervision is an effective approach to reduce the complexity of controller design and implementation. But hitherto its implementation has been restricted by the blocking problem.