The petrogenesis of eclogites scattered in gneisses on the northwestern margin of the Southern Shandong-Northern Jiangsu tectonic melange zone has been studied in this paper by petrological, mineralogical and petrochemical methods. Through our study, we have reached the conclusion that the protolith of eclogite is tholeiite formed in an island-arc environment. Geothermometry and geobarometry show that theP-Tconditions for the formation of eclogites areT788.35℃andP2.5 GPa. The formation of the eclogites is related to the subduction-collision orogeny between the North China and the Yangtze plate.