Abstract: The composition and function of parallel pipelines flow distribution test system was introduced. The impedance of plate-fin heat exchanger or cold box in the test system are substituted by the balancing valves, and in order to keep the consistency of the branch impedance, the balancing valves were calibrated by the calibration. The results show that the flow distribution characteristics of single phase in the parallel pipelines is uniform. Direct return arrangement of pipelines have a better uniform flow distribution characteristics than reversed arrangement of pipelines. Changing the inlet flow rate has little effect on the flow distribution characteristics. Enlarging the impedance of each parallel branch is beneficial to flow distribution characteristics.