The　agricultural　flood　irrigation　in　Jingyang　South　Platform,　Shaanxi　Province　caused　the　rise　of　groundwater　level,　which　induced　a　large　number　of　loess　landslides.　The　study　of　water　movement　in　unsaturated　loess　under　irrigation　is　the　premise　of　revealing　the　mechanism　of　loess　landslide.　In　this　paper,　the　changes　of　matric　suction,　volume　moisture　content　and　air　pressure　with　time　at　different　depths　of　unsaturated　undisturbed　loess　are　measured　by　indoor　soil　column　water　infiltration　test.　Air　pressure　at　each　point　of　the　soil　rises　to　about　98　Pa　in　a　short　time　after　the　test　beginning,　and　keeps　small　fluctuation　up　and　down　during　the　test.　At　the　end　of　the　experiment,　the　air　pressure　at　each　point　of　the　soil　returns　to　zero　in　a　short　time　after　the　upper　water　accumulation　is　eliminated.　During　the　test,　the　change　of　infiltration　rate　has　a　significant　corresponding　relationship　with　the　exhaust　phenomenon　at　the　top　of　the　soil　column,　and　the　air　resistance　significantly　reduces　the　infiltration　rate　of　water.　©　Published　under　licence　by　IOP　Publishing　Ltd.