The aim of present work was to assess the response of soil microbial activity and diversity to green manures under the organically managed grape-greenhouse in early spring. Hairy vetch, milk vetch, and red clover were seeded in fall, and enzymatic activities by dehydrogenase and fluorescein diacetate (FDA) hydrolase, and microbial diversities by Biolog EcoPlate TM and phospholipid fatty acid (PLFA) were characterized for soils sampled in early spring. Dehydrogenase activity and FDA hydrolytic activity did not differentiate the green manures but the average well color development of Biolog EcoPlate was higher in soils covered with red clover than control soil. Soil microbial functional diversity by Biolog EcoPlate differentiated the soils covered with hairy vetch and milk vetch, and Shannon diversity index by Biolog EcoPlate was higher in soils covered with hairy vetch than control soil. Principal component analysis of PLFA differentiated the soils covered with milk vetch from control soil.