Abstract: Abstract: Subsurface drainage has widely been constructed to discharge water and control the groundwater level against soil salinization in most arid regions. The main purpose of subsurface pipe is to discharge the salt from the soil profile under spring or winter irrigation. Thus, the appropriate layout parameters of subsurface drainage in arid and semi-arid areas can be different from humid regions. Therefore, it is highly necessary to investigate the influence factors of soil desalinization and salt discharge under subsurface drainage pipes in arid regions. In this study, there were four objectives: 1) to investigate the change of soil water content and salinity under subsurface drainage pipes with different layouts and irrigation quota; 2) to explore the time-varying process of flow flux and electrical conductivity under subsurface drainage pipes in each treatment, and thereby to determine the water and salt discharge amount of subsurface pipes with different layout and irrigation quota; 3) to analyze the influencing factors of desalinization rate in subsurface layout parameters; 4) to clarify the interaction of irrigation quota and layout parameters of subsurface pipes on the soil desalinization rate. Taking the Yanqi County, Xinjiang Uygur Autonomous Region of China as a study area, the field experiments were conducted in 2018 and 2020, where the irrigation quota was 490 mm for 2018, and 288 mm for 2020. Three layout parameters of subsurface pipes with every three levels were considered in the experiment, including three spacing (6, 10, and 20 m), three drain depths (0.8, 1.1, and 1.4 m), and three pipe diameters (90, 110, and 160 mm). An orthogonal experimental design was adopted to combine each parameter and level, where there were nine treatments in total. Multi-factors analysis of variance was made to clarify the significant influencing factors on the desalinization rate. The results show that the water content of the soil profile increased obviously before and after the experiment, whereas, the soil salinity relatively decreased under subsurface drainage. The duration of subsurface drainage ranged from 245 to 441 h during discharge. The flow flux of subsurface pipes increased rapidly at first, and then decreased slowly, whereas, the electrical conductivity was relatively stable, where the average electrical conductivity of drainage water was 12.65 mS/cm, related mainly to the salinity of soil profile. The accumulative amount of water and salt discharged from the subsurface pipe decreased significantly, with the decrease of irrigation quota. The soil desalinization rate presented a significant relationship with the subsurface pipe spacing and depth (P< 0.05 and 0.01, respectively) under the same irrigation quota. Specifically, it was negatively correlated with the spacing, but positively correlated with the buried depth, whereas, there was no significant relationship with the pipe diameter. Consequently, an optimal drainage depth and spacing are very necessary for the high efficiency of the subsurface drainage system in arid areas. In addition, the leaching quota is also the key factor affecting the desalinization rate. The buried depth of the subsurface drainage pipe is recommended as 1.4 m, and the drain spacing is 8 m, while the diameter is 90 mm for the study region, considering water-saving and engineering costs. In this case, the leaching quota of 300 mm can meet the national requirements of desalinization. This finding can provide a promising basis to choose appropriate parameters of subsurface pipe layout and irrigation quota in arid areas.