Abstract: In view of reservoir heterogeneity and incomplete subsurface data during reservoir evaluation of nonmarine facies,according to rock cores, well logging and seismic data of Jurassic in 6th and 7th districts at the NW margin of Junggar basin, taking sequence stratigraphy, sedimentology and logging geology as theoretical guidance, the sedimentary microfacies were analyzed, the logging evaluation of oil reservoirs was made, and the reserve distribution was illustrated. The J3q3 sand layer of Qigu Formation was evaluated comprehensively. The study shows that the braided river is dominated in the study area. Three microfacies, i.e. channel bar, braided channel and floodplain were identified, and the last is very limited. The oil reservoir distribution is controlled by fault and sedimentary microfacies. The favorable oil reservoirs are located in the channel bars of structurally high part close to the fault. According to the microfacies analysis, the reservoir logging evaluation and related reserve calculation, it was determined that the new incremental productive area is 8.37 km2, and the new incremental controlled reserve is 719×104 t. Two favorable target districts were optimized, four appraisal wells were proposed, and the scientific bases were provided for further reservoir exploitation in the study area.