Abstract: To ensure safe operation of the natural gas pipeline networks, reliability assessment method can be implemented to perform quantitative assessments and analyses of physical safety and overall gas-supplying capacities of natural gas pipeline networks. Researches related to such topics in China are still in their preliminary stages. This paper reviewed current researches related to reliability assessment techniques for natural gas pipeline network systems in China. Concepts and algorithms of commonly used reliability assessment indexes for the pipeline network systems have been studied in two aspects: work safety and gas-supply safety to introduce methods available for the reliability assessments for long-distance pipelines, pump/gas compressor stations and the overall pipeline network systems. In addition, methods used to determine reliability of system supplies and objectives have been reviewed to highlight importance and development of assessment techniques available for assessments of pipeline network system reliability.