Objectives: Located in a key position in the southern Central Asian Orogenic Belt, the Alxa Block provides an ideal window to evaluate the Permian tectonic setting and evolution.  Methods: Based on the field geological investigation in the Langshan region, northeastern margin of the Alxa Block, this study presents comprehensive research on the paleocurrent, sandstone components, and detrital zircon U- Pb dating from the Permian Dahongshan Formation.  Results: The original maximum flat surface of gravel from the Dahongshan Formation dips to SWW to NWW, revealing the paleocurrent during the deposition of the Dahongshan Formation was generally from west to east and also suggesting gravels from this Formation mainly come from the western Langshan. Detrital zircons from the sandstone samples with the minimum age peaks of 275 Ma and 278 Ma constraints the depositional age of the Dahongshan Formation no earlier than the early Middle Permian.  Conclusions: Paleocurrent data and detrital zircon age spectrum, coupled with sandstone components data support that the detrital materials of Dahongshan Formation originated from the Late Paleozoic magmatic arc, while the gravels were originated from the Alxa Block basement. Combined with the Late Paleozoic continental arc in the Nuoergong—Langshan tectonic belt, we suggest that the Dahongshan Formation was deposited in a retroarc foreland basin.