Developing　economic　controlled-release　fertilizers　(CRFs)　with　superior　performance　is　an　ongoing　and　important　research　area.　This　work　investigated　the　co-modification　of　acid-activated　attapulgite　(ac-AT)　to　optimize　its　surface　properties　for　polyurethane　(PU)　composite　applications,　specifically　in　the　coatings　of　CRFs.　The　modified　ac-AT　(MAT)　rods　were　obtained　through　treatment　with　2.0　wt.%　KH-560　coupling　agent　and　in-situ　grafting　with　stearic　acid　(SA).　Varying　the　addition　amount　of　SA　resulted　in　the　synthesis　of　different　MAT　fillers.　Along　with　the　adjustment　of　the　filling　amount,　the　properties　of　the　MAT/PU　composites　were　controlled.　Notably,　applying　1.5　wt.%　SA　onto　the　KH-560　treated　ac-AT　produced　MAT　with　a　contact　angle　of　100.8°,　enhancing　hydrophobicity　and　dispersion　within　the　PU　matrix.　Furthermore,　at　a　filling　amount　of　9.0　wt.%,　the　MAT/PU　composite　exhibited　the　most　favorable　properties　with　a　tensile　strength　of　2.37　MPa,　making　it　the　optimal　coating　for　CRFs　with　75%　nutrient　release　within　46　days　while　the　coating　efficiency　was　3.0　wt.%.　This　co-modification　approach　shows　great　potential　in　enhancing　filler　properties　and　promoting　their　application　in　organic　coatings.　©　2023　Wiley　Periodicals　LLC.