Abstract: A new discovery has been found in lower assemblage Chang-8 member of Yanchang formation in Xiasiwan oilfield,however,the research degree of tight sandstone reservoir in Chang-8 member is relatively lower and there is no breakthrough progress in tight sandstone reservoir exploration.In order to make clear the tight sandstone reservoir development prospects of Chang-8 member of Yanchang formation,according to the core,drilling,well logging and analysis of test data,the in-depth analysis of tight sandstone reservoir accumulation conditions has been carried out.The results indicate the tight sandstone reservoirs are of good accumulation conditions,the reservoir accumulation and enrichment are mainly controlled by sedimentary micro-facies,source rocks and high-quality reservoirs.Through comprehensive analysis,LP163-LP177 and X41-X45 well blocks are considered to be of better accumulation conditions,and can be taken as the favorable exploration and development area in the next step.