Hydrophobic　property　of　metal-organic　frameworks　(MOFs)　is　not　only　important　for　their　stability　improvement　but　also　has　a　profound　effect　on　the　performance　of　many　applications.　The　essence　of　coordination　bonds　led　to　most　of　the　MOFs　are　hydrophilic　and　hydrophobic　MOFs　are　generally　achieved　by　hydrophobic　modification　of　pore　surface.　Here,　we　report　the　systematic　regulation　of　water　adsorption　and　hydrophobic　property　of　a　classical　MOF　MIL-101(Cr)　through　post-synthetic　modification.　The　contact　angle　(CA)　of　modified　MIL-101　could　vary　from　17.9　degrees　to　146.5　degrees　by　changing　the　alkyl　chain　length　of　primary　amines.　The　water　adsorption　capacity　and　step　pressure　can　also　be　tuned　correspondingly.