Abstract: Exergy analysis has been extended from general energy analysis to thermoeconomic analysis and environmental analysis,i.e.,sustainability analysis.Some fundamental studies of exergy analysis become more important.This research emphasizes the importance of the strict concept of standard state and the new values of standard thermodynamic properties.Based on the concept from the ISO 13600 series standards of the technical energy system,the IUPAC’s rule about thermochemical standard properties,and the up-to-date and authoritative data of the Gibbs free energy of standard formation,the model of environmental-reference-state by Kameyama et al is modified,which consists of selected standard compounds at 298.15K and 1bar in the atmosphere, hydrosphere or geosphere.A new data system of the element standard exergy involving 80 kinds of ordinary elements is proposed.In addition,the example of a homogenous liquid mixture of ammonia and water given in the paper suggests that standard exergy is the principal value of exergy function of the mixture.