Early Cretaceous potassium-riched alkaline volcanic rocks were discovered in the Suhongtu area, Inner Mongolia. These volcanic rocks display higher total alkaline contents (K₂O+Na₂O=5.20%~8.92%), K₂O/Na₂O (K2O/Na2O=0.59~1.03) and TiO₂ (1.59%~2.05%) and characteristics of shoshonites series rocks. Chondrite normalized rare earth element patterns and primitive mantle normalized trace element patterns show slightly positive and negative Eu anomalies (δEu=0.88~1.11) and the enrichment of large ion lithophile elements (LILE), light rare earth elements (LREE) and high field strength elements (HFSE). Suhongtu volcanic rocks show similar geochemical characteristics to those of Siziwangqi and Southern Baiyun’ebo volcanic rocks. These volcanic rocks did not experience obvious contamination of crustal materials. Negative Nb and Ta anomalies probably imply the influence of the subducted slab of Paleo-Asian Ocean crust. Trace elements and isotopic analysis indicate that the Suhongtu and Siziwangqi shoshonites magmas were derived from EMⅠ enrichmental asthenosphere mantle altered by materials from the subducted slab of the Paleo-Asian Ocean crust, and the Southern Baiyun’ebo volcanic rocks was from a less-degree enriched source. However, their petrogenesis is similar to the depleted mantle source with various degree of enrichment. In combination with the regional geology, the middle and western part of the north margin of Northern China Craton (NCC), along which Siziwangqi, Southern Baiyun’ebo and Suhongtu volcanic rocks distributed, probably showed an similar extensional environment after orogenic period in Early Cretaceous. After the closure of the Paleo-Asian Ocean in Late Triassic, a NS-trending compressive process developed in the north margin of NCC, which led the thickening of crust and the delamination of lithosphere. Then the remelting of the subducted slab of the Paleo-Asian Ocean crust, and the melt resulted in enrichment of the depleted asthenosphere mantle, and the upwelling and partial melting of the enriched mantle asthenosphere mentle formed EW-distributed Early Cretaceous shoshonites.