Abstract: Two layers of the larger-sized bioherms are identified in the Devonian Lazhuglung Formation in Sanchakou, northwestern Xizang. The bioherms occur as superimposed reefs have a thickness of 7.28 m for the lower bioherms, and 40.98 m for the upper ones, and consist of reef batholith, reef core and reef crest. The reef front talus, reef frame, interreef and backreef deposits are observed in the profile. The discovery of the Devonian bioherms may offer some new thoughts on possible future direction of the oil and gas exploration in the study area.