The Zongzhuo mélange in southern Tibet is a major component of the Yarlung-Zangbo suture zone that marks the contact between Indian and Asian plates. In this study, detailed field investigation and petrologic studies and detrital zircon geochronologic studies of sandstones were carried out on the Zongzhuo mélange in Baisha area, Gyangze county to better understanding its provenance and tectonic setting. The Zongzhuo mélange comprised by exotic blocks and unmetamorphic shale and mudstone ‘matrix’. Exotic blocks are several centimeters to tens of meters in size, and comprise a variety of lithologies including sandstones, cherts, basalts, limestones and conglomerates. Detrital modes of the sandstones are composed of dominantly volcaniclastic grains and subordinately quartzes and feldspars, similar to sandstones from the Xigaze forearc basin. Detrital zircon U-Pb ages from an exotic sandstone block are mainly clustered at ~70-110Ma, with an peak age of ~90 Ma. The youngest age is 62±1Ma, which indicate the age of the Zongzhuo mélange was at least extent to Paleocene. Occurrence of abundant volcanic detritus and young-aged zircon suggest that the Zongzhuo mélange contain significant amount of materials derived from the Gangdese volcanic arc north of the Yarlung-Zangbo Suture Zone. This further suggests that the Zongzhuo mélange were formed after the India-Asia initial collision happened.