Intermediate block valve shall be installed in order to reduce leakage in case of a pipeline rupture. For large-diameter gas pipeline, main startup distinguishing method of the block valve is called as Pressure-Drop Rate method. At present, the common set value of pressure-drop rate for such large-diameter pipeline as West-to-East Gas Pipeline is 0.15 MPa/min. However, it will bring about such some problems as malfunction, act delay and refusal if the set value for all long-distance pipelines with different diameters and operating conditions are the same. Hence, it is very important to study the set valve of intermediate block valves in practical works. OLGA software is applied to conduct dynamic simulation of a pipeline segment between two compressor stations o(some gas pipeline and studied is the effect of such parameters as rupture size, diameter, operating pressure, rupture location and flow rate on pipeline pressure drop rate, which can provide valuable reference for set value determination and modification.