Long　chain　branched　polypropylene/clay-supported　calcium　pimelate　(LCBPP/CaHA-OMMT)　composites　and　their　foams　were　prepared　using　self-made　CaHA-OMMTs.　The　CaHA-OMMT　showed　high　β-nucleation　efficiency,　especially　that　with　larger　initial　interlayer　distance　could　induce　89%　of　β　crystal　in　LCBPP　with　a　dosage　of　0.5%.　Clay　layers　were　mostly　exfoliated　in　the　composites　with　low　CaHA-OMMT　content,　while　intercalated　structure　was　dominant　and　agglomeration　occurred　when　the　content　of　CaHA-OMMT　was　higher　than　2%.　The　composite　foams　were　prepared　with　improved　compression　molding.　The　cell　structure　of　the　composite　foams　is　improved,　that　is,　the　density,　cell　size,　and　cell　size　distribution　decreased,　and　the　cell　density　increased　compared　with　that　of　LCBPP　foam.　The　minimum　average　cell　size　of　LCBPP/CaHA-OMMT　foams　was　77　μm　and　the　maximum　cell　density　was　2.8　×　106　cells/cm3　with　the　CaHA-OMMT　content　of　2%.　It　is　concluded　that　there　are　two　requirements　for　high　nucleation　efficiency:　the　CaHA　was　supported　on　OMMT　layers,　and　the　OMMT　platelets　were　dispersed　well　and　exfoliated.　The　compression　properties　of　the　composite　foams,　including　compression　modulus,　energy　absorption　density　and　failure　strength　increased　first　and　then　decreased　with　the　increase　of　CaHA-OMMT　content.　©　2021　Society　of　Plastics　Engineers.