When water flows through the vadose zone,there is not only water inflow but also air inflow.In this study,a one-dimension infltration and two-dimension infiltration experimental apparatus was designed and built up.We got the two-phase flow field by driving the airflow with water infiltration and recorded and monitored the water accumulative infiltration volume,wetting front and the air pressure within the twophase flow field to study the two-phase flow.One-dimension and two-dimension two-phase flow experiments were conducted to determine effect of air compression on the infiltration of water under different air outflow rates,the change in air pressure and the air movement.The pressure sensors connected with the automatic pressure monitor system were used to monitor and record the change in air pressure in 1-D and 2-D soil column.The micro gas flowmeter with valves was connected with the soil column at its bottom to control and regulate the air outflow rate.In 1-D experiment,we found that without controlling the air outflow the water inflow rate was reduced compared with the water inflow rate under the condition,as observed by other researchers.When the air outflow rate varied,the water inflow rate changed accordingly,but always remained bigger than the former.In 2-D experiment,it is found that the water inflow-rate in vertical direction was bigger than that in horizontal direction.Finally,we got air pressure contour figures at different times.From these figures,it is discovered that the airflow was most vehement along the line between the water trench and the air vent in the bottom of the soil box.