Abstract: Based on the research status of oil-water emulsion and phase inversion, viscosity measurement and frictionprediction at home and abroad, this paper analyzes the causes of error in oil and water flow friction prediction andcountermeasures. Factors affecting the accuracy of oil and water flow friction calculation are levels of oil and wateremulsion, phase inversion conditions, variation of oil-water flow type and oil-water viscosity measurement, the root causesare the quite different flow characteristics and composition of oil and water mixture in real pipeline and rotational rheometer, or loop simulation test apparatus. For this reason, the paper proposes a research approach proceeding from the establishmentof intrinsic link between oil and water flow pattern in test system and real pipeline, in the hope to provide a reference to thein-depth and systematic research in flow friction prediction on heavy oil and water mixture.