Abstract: The application of mixed transmission technology for wet natural gas can reduce number of operators at condensate gas fields in adverse offshore, desert, Gobi and beach environments and decrease producing cost. In practical operation, flow of wet natural gas inside pipeline is always in slow transient state. From basic rule of fluid mechanics, establishes a mathematics model equation describing transient flow of wet natural gas transmitted in pipeline, makes simple treatment on model equation and designs a concrete calculation thinking. Based on transmission boundary condition, gives calculation method for value of dynamic model equation, pipeline discrete form, memory method for coefficient and difference equation. Simulative Calculation is made on the pressure at each point along the pipeline during gas pipeline storage and supply processes, flow velocity of gas-liquid phase and changing rule with time for liquid-holdup in pipeline.