Abstract: The Triassic strata are widespread in the Qamdo-Riwoqe region,eastern Xizang.In the light of the outcrop sections in this region,four third-order sequence boundaries have been distinguished for the Late Triassic strata. One is assigned to the type 1 sequence boundary and the other three belong to the type 2 sequence boundary. Correspondingly,four third-order sequences are recognized:one type 1 sequence and three type 2 sequences.These third-order sequences may be correlated,and owe their origin to the interaction of inactive tectonics,increasing sediment supply and global sea-level changes.