There is an increasing need for enterprise architecture in numerous organizations with complicated systems with various processes. Support for information technology, organizational units whose elements maintain complex relationships increases. Enterprise architecture is so effective that its non-use in organizations is regarded as their institutional inability in efficient information technology management. The enterprise architecture process generally consists of three phases including strategic programing of information technology, enterprise architecture programing and enterprise architecture implementation. Each phase must be implemented sequentially and one single flaw in each phase may result in a flaw in the whole architecture and, consequently, in extra costs and time. If a model is mapped for the issue and then it is evaluated before enterprise architecture implementation in the second phase, the possible flaws in implementation process are prevented. In this study, the processes of enterprise architecture are illustrated through UML diagrams, and the architecture is evaluated in programming phase through transforming the UML diagrams to Petri nets. The results indicate that the high costs of the implementation phase will be reduced.