The Dahuabei granite and the Xishadegai gabbro diorite are located in the Wulashan area in the middle of the northern margin of the North China craton and are located in the middle part of the Yinshan uplift. They are significant areas for the researching of the Paleozoic interaction between the paleo-Asia Ocean plate and the North China plate.In this paper, according to the zircons LA-ICP-MS U-Pb dating, rare earth and trace element analysis, the age ofmedium-fine granodiorite, medium-coarse granodiorite, medium coarse granulite and medium fine grained diorite were 332.8 ± 1.2Ma, 333.8 ± 1.3Ma, 332.6 ± 1.1Ma and 333.2 ± 1.9Ma.The results show that both graniteand gabbro are belong to the Early Carboniferous magmatism.Dahuabei granite with rich silicon, quasi-aluminum - weak permanganate, high alkali, relatively potassium-rich, is a high-calcium alkaline series,and belongs to light rare earth enrichmentfeatures, extensive palaeo-diorite inclusions in the margins of rock mass, and the patterns of REE are basically the same. All kinds of data show that the two rock masses are closely related in genesis.The gabbro inclusions are extensively developed in the margins of the rock mass, and the distribution patterns of rare earths are basically the same. All kinds of data show that the two rock masses are closely related in genesis.Based on the regional geological background and tectonic interpretation, it is concluded that the Dahuabei granite bodies and the gabbro bodies are formed during the arc-back extrusion to extensional environment during the subduction of the ancient Mongolian plate to the North China Plate.