Abstract: The lamprophyre in Dongxiaoshan area of Linyi City, Shandong Province, belongs to the weak aluminum ultra-potassic type with high Ba, Th and P, enrichment of LREEs and distinct fractionation between LREEs and HREEs, indicating the lamprophyre is contaminated by crustal materials during the late emplacement. The lamprophyre rich in LILEs and HFSEs shows that the magma mainly comes from the enriched mantle, further revealing its source area is contaminated by the crustal materials. Two chrome diopsides are selected by artificial heavy concentrate method to calculate the formation temperature of 1 180 ℃ and pressure of 5.8 Gpa respectively, with the corresponding depth of about 180 km, which is consistent with the formation depth of diamond.