The Silurian Balonggonggaer Formation is widely distributed in the South Qilian Mountains and in recent years Neoproterozoic Guaizhangshan Group were found within. It is of great significance in deciphering its sedimentary time, provenance and affinity with adjacent plate. In this paper, we conduct LA- ICP- MS zircon U- Pb dating for biotite plagioclase quartz schist and quartz schist from the Guaizhangshan Group in southern Danghe Mountains. Detrital zircon ages show that the weighted average ages of the youngest zircons in the three samples are 794±10 Ma, 746±65 Ma and 713±75 Ma, indicating that the Neoproterozoic rocks were deposited after 794 Ma while volcanic activity began ～740 Ma. The detrital zircons were largely concentrated in the age range of 867～700 Ma and indicated that the basement rocks of the Quanji and the Central Qilian blocks may have provide the detrital material. This group of ages is an indicator of the disintegration of the Rodinia supercontinent.After comparison with the Quanji, the Central and the Qaidam blocks, North China plate, Australian plate and Yangtze plate, the U- Pb age spectra of detrital zircons shows that the South Qilian block has good affinity of its surrounding massif and the Yangtze plate, but its provenance was mainly from Quanji block and Central Qilian block while it was less related to Yangtze plate.