The design of a complex system requires both functional and behavior representation. Formal methods are mathematical based techniques used for specifications of properties hardware and software systems. The Znotation is a formal technique used for capturing functionality. Automata theory is a powerful tool to capture their control behavior. As a result, integration of Z and automata will be an effective tool for modeling of complex systems. The deterministic and nondeterministic finite automata are abstract models of machines used for capturing behavior of systems. Because both of these approaches have different time and space complexitytherefore each one has advantages over the other. Consequently, there must be an automated conversion procedure from nondeterministic to deterministic finite automata and vice versa. In this paper, such a formal conversion is described using Z notation. The specification is analyzed and validated using Z/EVES toolset.