To improve the current status of soil salinization in the Hetao irrigation area and increase crop yields， subsurface drainage experiments were carried out in saline-alkali soils in the lower reaches of the Hetao irrigationarea.Three treatments on the depth and interval combination of subsurface drainage pipe were setup，including the buried -depth of 1.2 m with the interval of 30 m(T1)，and the buried depth of 0.8 m with the interval of 20 m(T2).Changes in soil salinity and sunflower yield were analyzed to compare the effects of different subsurface drainage treatments onsoil salinity in thearea.The results showthat:1)After the underground drainage pipe wasburied，the salt contentof the surface soil(0～20cm)changed most drastically，followed by the middle layer(20～60cm)，and thedeep layer(60～100 cm)was more stable.During the whole observationperiod，the soil salt content of the surfacesoil in the subsurface drainage control area was reduced from moderate to severe salinization level(5～ 8 g·kg-1)to mild to moderate level(2～ 6 g·kg-1).2)The closer to the horizontal distance of underground pipe，the better thesoil desalinationeffect.The maximum desalination rates of T1 and T2 in 0～ 100 cm soil layer were 32.04% and42.44%，respectively.3)The fitting equation of the soil leaching curve showed that under the same irrigation volume and soildepth，the soil leaching salt effect of T2 was better than that ofT1，and the further the horizontal distance from the undergroundtube，the worse the soil salt leachingeffect.4)The sunflower yield of T1 and T2 were significantly higher than that of noburied pipe control(T0)(P<0.05)，and the yield was increased by 34.29% and53.51%，respectively，compared withT0. The research results can provide a theoretical basis for improving the saline-alkali land in Hetao irrigation area by using subsurface pipe drainage technology.