Soil　column　tests　were　conducted　to　investigate　the　effects　of　grass　type　on　water　infiltration　in　a　three-layer　landfill　cover　under　drying　and　wetting　conditions.　Five　soil　columns　were　prepared,　including　one　bare,　two　Bermuda　grass-planted　and　the　other　two　vetiver-planted.　During　the　drying　period,　the　suction　of　vetiver-planted　soil　column　was　the　largest,　while　that　of　bare　case　was　the　lowest.　During　the　wetting　period,　the　infiltration　rate　shows　a　bimodal　form　due　to　the　contrasting　hydraulic　properties　of　different　soil　layers.　The　infiltration　rate　of　vetiver-planted　soil　column　was　the　lowest,　followed　by　Bermuda　grass-planted　and　bare　cases.　Correspondingly,　the　vetiver-planted　soil　column　retained　the　maximum　suction　and　the　deepest　ponding　depth　during　rainfall.　This　was　likely　due　to　the　larger　leaf　area　and　deeper　roots　of　vetiver　than　those　of　Bermuda　grass,　thus　inducing　the　maximum　initial　suction　by　root　water　uptake　before　rainfall　and　reducing　the　water　permeability　by　root　occupations　of　soil　pores.　These　results　show　that　vetiver　is　more　effective　than　Bermuda　grass　to　reduce　water　percolation　through　the　three-layer　landfill　cover.