The water transmission line of Taihu Reservoir is located in Xunwu County，and the pipelines are mainly arranged along the current situation of the national gully，the 206 State Road and the high-speed connecting line side ditch.Along the line，the terrain is complicated and the undulations are large.Under the condition of no decompression box，the local pressure of the pipeline operation is too high，the maximum hydrostatic pressure is as high as 162m，and the pressure changes greatly.Due to the poor operating conditions of the water pipelines，the squid will pose a serious threat to the traffic along the line and surrounding people’s lives and property.In order to reduce the pressure in the pipeline and reduce the risk of pipe explosion，this design proposes the installation of two decompression boxes at the inlet of the pipeline and the highest point along the pipeline.By limiting the operating water level in the decompression box and adjusting the opening of the regulating valve before the decompression box to control the overflow flow when the operating water level in the decompression box overflows，the operating pressure of the pipeline is effectively reduced，the pressure variation is reduced，and the pipeline operation is more stable.