Abstract: Emergy analysis is an important method to current energy research and systematic sustainability assessment, which characterizes all products and services in equivalents of solar emergy.In this paper, emergy flows, emergy input and output, and emergy index (EIR, EYR, ELR, EST) of three orchard systems were characterized by emergy analysis.Our results showed that the largest energy flows in all systems is associated with labor, FCMP fertilizer and sunlight.In addition, 66.3%-73.9% of the total emergy inputs to the orchard system was economic resources.In the end, our results suggest that the terracing orchard system has the lowest environmental loading ratio (ELR) due to the reduced soil erosion and the highest emergy sustainability Index (ESI) , for it is based on the 100%living mulch compared to the other two clean tillage systems.