Alkali-metal　(AM)　ion　batteries　have　been　attracting　great　attention　due　to　the　high　specific　capacity,　fast　charging　rate,　and　good　reversibility.　In　this　work,　the　adsorption　and　diffusion　of　Li,　Na,　and　K　atoms　on　a　twodimensional　(2D)　group-IV　monochalcogenide,　germanium　selenium　nanosheet　(GeSeNS),　have　been　systematically　investigated　by　first-principles　calculations.　The　considered　AM　atoms　could　form　strong　binding　and　exist　in　stable　configuration　with　GeSeNS.　A　semiconducting　to　metallic　transition　induces　an　excellent　electrical　conductivity　after　AM　intercalation　on　GeSeNS,　that　is　essential　for　an　optimal　anode　material.　Our　results　show　that　the　low　energy　barriers　of　AM　atoms　diffusion　along　zigzag　direction　are　0.329　(Li),　0.175　(Na)　and　0.132　(K)　eV,　respectively,　which　are　lower　than　values　of　the　commercial　graphite　anode　material　and　corresponding　to　ultrafast　charge/discharge　capability.　The　average　voltages　are　about　1.82,　1.45　and　1.28　V　for　the　LixGeSe,　NaxGeSe　and　KxGeSe　systems,　respectively.　Hence,　our　results　suggest　that　GeSeNS　could　be　a　potential　electrode　material　for　application　in　low-cost　AM　ion　batteries　with　a　high　rate　capability　and　high　charging　voltage,　thus　encouraging　further　experimental　work.