Abstract: In view of the fact that most of the current assessment methods for integrated energy reliability are oriented to microgrid systems， it is difficult to analyze the reliability of regional integrated energy systems from the perspective of system topology. A method for evaluating the reliability of regional integrated energy systems applying complex network theory is established. Firstly， taking regional integrated energy system as the research object， basic structure of the regional integrated energy system is introduced and the feasibility of the application of complex network theory is analyzed. Secondly， by improving the distance parameters within the complex network， a weighted complex network model including network characteristic is constructed. On this basis， from the perspective of system network topology， reliability evaluation indices including nodes and the system as a whole are proposed. Finally， the validity and applicability of the method are verified by constructing actual test cases. This paper explores the application of complex network theory in reliability assessment of regional integrated energy systems， and provides guidance on the reliability level for future planning and construction of regional integrated energy systems.

Key words: complex network, regional integrated energy system, reliability, weak link