Taking the Faulted Block Guan 104,Wangguantun Oilfield,Huanghua Depression,Bohai Bay Basin as an example,this paper deals with flow units study of braided river reservoir. The step of research includes two foldsThe first is the analysis of seepage barrier and connected sandbody,and then the analysis of seepage variation. The main microfacies are midchannel bar,braided channel and overbank. The types of seepage barriers include shale and cemented belts. Through seepage variation analysis, four kinds of flow units were classified in the braided river reservoir of ZaoⅠ and ZaoⅡ oilcontaining interval Faulted Block Guan104. Flow unit I is characterized by mediumhigh porosity and permeability reservoir,mainly distributed in midchannel bar and the core of braided channels. Flow unit II is characterized by medium porosity and medium to low permeability reservoir,mainly distributed in braided channels. Flow unit III is characterized by medium to low porosity and low permeability reservoir,mainly distributed in the margin of channels and overbank. Flow unit IV is in fact nonreservoir with extremely low permeability. Lastly the distribution model of flow units of the studying area was made through the analysis of seepage barrier and seepage variation. The study is very important to optimize the oilfield development adjustment plan.