Some diorite stocks developed in the Xar Moron fault belt in Linxi county, Inner Mongolia. They intruded into the Shuangjing schist and display variable degrees of deformation. This study presents the petrology, geochemistry, a LA-ICPMS U-Pb zircon age and a hornblende ⁴⁰Ar-³⁹Ar age of the diorite. The research area then entered post-orogenic extension, while further east the Paleo-Pacific plate subducted beneath the North China Craton. The combination of regional post-orogenic extension and distant subduction led to alternating compression and extension in the Jurassic in what is now northeastern China. After the change in the subduction direction of the Paleo-Pacific plate in the Late Jurassic, the tectonic environment in northeastern China finally became extensional and the region entered the West-Pacific tectonic domain.