With the implementation of the Smart Grid, communication network and power systems will be more closely associated. Therefore the reliability and security of systems and information in the IT and communications infrastructures has a great impact on the power system reliability. And it is necessary to perform research on the assessment methodology of the reliability and security of the power communication network. In this paper, a systematical reliability and security assessment process for the electric power communication network is demonstrated. A three-level assessment hierarchical architecture is proposed. According to the proposed three-level hierarchical architecture, an application system is developed to assess the reliability and security.