Legume green manure is extensively planted to improve soil fertility in crop field. However, the application of legume in Eucalyptus plantation is still limited and depends on site specific and species. Therefore, the objective of this study was to determine the effects of green manure interplantation on soil fertility and plant growth of Eucalyptus plantation in a short term. A field experiment of one year was established to investigate the green manure growth, forest soil nutrients and Eucalyptus plant growth inter-planted with two legume species (Tephrosia candida, TC and Sesbania cannabina, SC) at south subtropical China. Legumes were inter-planted in linear among the tree space of Eucalyptus stand. Result showed that the green manure inter-plantation increased soil organic matter by 9.66% of TC and 18.44% of SC. Soil available nitrogen, phosphorus and potassium were improved significantly by the legume treatments as well. The increment of height and diameter at breast height of Eucalyptus during the experiment was significant in legume treatments. Thus, the timber volume increment was improved significantly by 46.81% of TC and 35.47% of SC compared with the control treatment. Therefore, the inter-plantation of legume green manure under the Eucalyptus plantation is effective to improve soil fertility and tree growth. Such a measure is potential and referenced for the sustainable forest management.