Abstract: In multiphase conduit flow, the main factors that influence drawdovm are pressure, pipe diameter, roughness of conduit, and gas and fluid flow rates, while that influence liquid holdup are pressure, pipe diameter, and gas and fluid flow rates. In view of the characteristics of highly viscous crude, special calculation models are used and software for computing drawdown and liquid holdup are programmed. The influential factors of drawdown and liquid holdup are analyzed in combination of case calculation.