Located at easternmost part of the Tethyan_Himalayan tectonic belt, the Qiongduojiang is one of the most important parts of southern Tibet metallogenic province, and has been considered as one of the key parts of the southern Tibet detachment system. Phanerozoic granitoid intrusions of varying size and occurrence are well_developed duo to multiple orogenic events from early Paleozoic to Tertiary. Some of these intrusions show an intimate relation with various metamorphic core complexes. To clarify the genetic type and geochemical features, two typical monzogranite bodies, that are associated with the Qiongduojiang metamorphic core complex, have been selected for the geochemical studies. Systematic chemical analyses on a number of fresh whole_rock samples from the Zhonggenai monzogranite ring and Qingri monzogranite stock indicate that both of these two rock bodies bear the characteristics of mantle_and crust_derived granitoid intrusions, not only in petrological observations and mineralogical assemblage, but also in major, trace and rare earth elements. The characteristic ratios of some trace element agree well with the typical shoshonitic igneous rocks. Based on the geochemical studies, combined with field geological evidences, we concluded that both the Zhonggenai monzogranite ring and Qingri monzogranite stock could be the result of the interaction of deep_rooted granitoid magma (mantle_derived ) and upper crust. Most of these granitoid intrusions occurring in the Qiongduojiang area were emplaced along a detachment zone during a large_scale extensional tectonic event caused by the Miocene post_collision orogeny (Mid_Himalayan time period). Meanwhile, some of these granitoid intrusions played an important role during the formation of various metamorphic core complex occurring in southern Tibet.