Based on detailed field survey of oil sand outcrops at the top of the middle Triassic Upper Karamay Formation and on the bottom of lower Jurassic Badaowan Formation in Tuziakeneigou on the northwest edge of Junggar basin, the authors measured 11 single sand beds in the oil sand outcrop of Upper Karamay Formation whose lithology is mainly grayish-brown pebbly coarse sandstone and medium-coarse sandstone, and identified 12 single sand beds which are products of multistage migration and superposition of channels in the oil sand outcrop located on the bottom of Badaowan Formation, where every single sand is composed of fining-upward positive rhythm composed of pebbly sandstone, medium coarse sandstone, fine sandstone and siltstone. Thin section analysis reveals that oil sand beds are mainly lithic sandstone and the content of feldspar and quartz is very low, which indicates that rock compositional maturity is low, stability of sandstone is in a low degree and these beds are fairly close to the source area. Textural maturity of sandstone is in a medium degree. In Upper Karamay Formation, lake and delta sedimentary facies, 2 subfacies composed of shore and shallow lake and braided delta front and 3 microfacies composed of lacustrine swamp, subaqueous distributary channel and interdistributary bay were recognized, and it is found that oil sand beds are mainly developed in the subaqueous distributary channel sand bodies, with a high oil content of 9.62%， the average porosity of oil sands of 28.6%, and the average permeability of 65.3×10-3μm 2. In Badaowan Formation, 3 sedimentary subfacies were recognized, i.e., riverbed, bank and alluvial flat deposit of braided river, with 5 microfacies, namely, channel lag, mid-channel bar, natural levee, alluvial flat and back swamps. The oil sand beds are mainly developed in the mid-channel bar sand bodies of braided river, with an oil content of 5.8%, the average porosity of oil sands of 31%, and the average permeability of 2602×10-3μm2. It is thus concluded that oil sand beds in Tuziakeneigou have good reservoir quality and oil-bearing property. Group composition of oil sand beds is mainly non-hydrocarbon and asphaltite, with only a small amount of saturated hydrocarbon and aromatic hydrocarbon, reflecting the serious degradation of oil sands.