Abstract: In order to explore the feasibility of reduced-scale test in the static airtightness study of high-speed train, the static leakage process of high-speed train was studied by numerical simulation and model test.Based on the static leakage model theory, the relationship among equivalent leakage area, the leakage time of the reduced-scale model with reduced-scale ratio were deduced.The 1∶1,1∶5,1∶10 and 1∶20 static leakage process of reduced-scale model was calculated by numerical simulation method.The relationship between reduced-scale model and static leakage time of train was verified, and the relationship between reduced-scale ratio and air velocity in orifice was clarified.A 1∶20 reduced-scale test system of train airtightness was established, and the static leakage process of train was reproduced.The influence of initial pressure on static leakage time is studied using the reduced-scale test system.The results show that the static leakage time of high-speed train is inversely proportional to the reduced-scale ratio.The relative error of static leakage time using the 1∶20 scale-model test system with the full-scale test results is 3.02%.And the maximum relative deviation of repeatability tests is 2%,which shows a good performance of accuracy and reliability.The maximum relative error of leakage time from 3 kPa to 1 kPa is 3.26%,when the initial internal pressure of the reduced-scaled model is 5 kPa, 4 kPa and 3 kPa respectively, which indicates that the static airtightness of high-speed train has no concern with the initial internal pressure.The findings can provide theoretical and data support for the reduced-scale model test studies on the air tightness of high-speed trains.