【Objective】In order to explore the distribution law of crystallization blockage in tunnel drainage system under the action of groundwater seepage, a laboratory simulation test of crystallization law of EmeishanHanyuan high-speed tunnel drainage system was put forward.【Methods】Based on the Liaoshan tunnel project of Emeishan-Hanyuan High-speed, a 1∶5 indoor simulation test of tunnel drainage system was established, and a test solution with the same ionic composition was configured according to the analysis results of in-situ groundwater sampling.【Result】The crystal stacking mode is mainly a large amount of stacking, which belongs to the isomeric crystal type, and the main component is calcite type calcium carbonate; With the increase of water flow, the crystallization amount increases, and the crystallization rate is faster, among which, the cumulative total crystallization under the condition of 266.8 mL/s water flow at the lateral drainage outlet is the highest; The moderate slope of the drainage pipe is conducive to the formation of crystals in the tunnel drainage pipe; The total amount of crystallization at the drainage pipe joint (30%) ＞ horizontal drainage outlet (27%) ＞ horizontal drainage pipe (19%) ＞ vertical drainage pipe (15.2%) ＞ circumdirectional drainage pipe (8.3%). The key positions of crystallization blockage in the tunnel drainage system are the drainage system interface and horizontal drainage pipe outlet.【Conclusion】The distribution law of crystal blockage in drainage pipe is effectively analyzed, which is of great significance for ensuring smooth and effective operation of tunnel drainage system.