To provide a simulation calculation method for a liquid pipeline network capable of executing the calculation of the pipeline network provided with a pump or the like at the same speed as a conventional method by forming simultaneous equations by an equation similar to a normal pipeline even in the case that a pressure non-continuous part and an external equipment are provided.

A flow rate Qi in the respective pipelines (i) of the liquid pipeline network is indicated by the product Ki.ΔPi1/2 of a pressure difference ΔPi between front and back nodes and the reciprocal Ki of pipeline resistance. In the case that the pump is provided in the pipeline, a differential pressure ΔPp by the pump is added to the ΔPi and ΔPi=ΔPi+ΔPp is attained. In the case that a check valve is provided in the pipeline, the reciprocal Ki of the pipeline resistance is applied as it is in the case that the pressure difference ΔPi in a direction where the check valve does not act is positive, the flow rate Qi is replaced with 'O' in the case that the pressure difference ΔPi is negative, the whole is indicated by the same equation Qi=Ki.ΔPi1/2, it is solvent and the flow rate of the respective pipelines is calculated.