Xihouhaozi pluton is located in the north of Siziwang Qi area, northern North China Craton. Cameca IMS-1280- SIMS zircon U-Pb dating indicates that it was emplaced at 266Mahansi-font-family: calibri; mso-hansi-theme-font: minor-latin">+2Ma. Monzogranite, as the dominant composition, has abundant large-size muscovites. Geochemical analyses show that the pluton is characterized by high SiO2 hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">(75.21%-76.69%hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">), A/CNK ratios hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">(mostlyhansi-font-family: calibri; mso-hansi-theme-font: minor-latin">〉l.1hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">) and normative corundum abundances hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">(mostlyhansi-font-family: calibri; mso-hansi-theme-font: minor-latin">〉l%hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">). Furthermore, the Xihouhaozi granite displays strong negative Eu anomalies hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">(~Eu=0.03-0.11hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">), striking Ba, Nb, Sr and Ti depletions, and slight Cs, Rb, Th and Pb enrichments. It presents a spec- tacular M-type tetrad effect in the P,.EE distribution patterns as well as non-CHAIkAC hansi-font-family: calibri; mso-hansi-theme-font: minor-latin">(charge-and-radius-controlledhansi-font-family: calibri; mso-hansi-theme-font: minor-latin">) trace element behavior. Tectonic discrimination diagram shows that the pluton might have been formed in a syn-collisional tectonic setting. In combination with regional geology, the authors hold that the Xihonhaozi granite belongs to highly fractionated peraluminous S-type granite and was generated during the continent-continent collision in the late Permian period. During 270-260Ma, a synconllisional granitic belt was formed in Siziwangqi area, which constrained the closure of the Solonker suture of the North China Craton with southern Mongolia in the late Pemaian period.