Abstract: Oil and gas reserves, as one of the important resources, need to be changed into assets and commercialized under market economic conditions. The essence of changing oil and gas reserves into assets is to determine the value of economically recoverable reserves. Based on analysis of the characteristics of oil and gas reserve assets and the influential factors of reserve assets value, cash flow analysis is introduced to calculate the reserve assets value of Liaohe oilfield. The method and steps of calculating reserve assets value through cash flow analysis are detailed in this paper. The determination of oil and gas reserve assets value provides a sound foundation for oil and gas reserves going into markets, and also provides a decision basis for exploration and development.