High fraction of inorganic compounds filled polymer composites with lightweight character show a potential application on building and transportation. In this study, super‐high fraction of organic montmorillonite (OMMT>30%) filled Polyamide 6 (PA6) foams were prepared via a solution foaming. The influence of OMMT content on structures and properties of foams was studied. When the OMMT content was higher than 50%, the surface of cells turned from smooth to nest‐like appearance. The addition of excessive clay depressed the crystalline behavior of PA6 during foaming. However, it did not damage the compressive mechanical properties of foams. PA6 macromolecules played a role of binder, endowing interfacial strength and structural integrity of cell walls. With the increase of OMMT loading content from 33% to 75%, the composite foams showed an increased specific moduli from 2.8 to 4.1 MPa. The current work realized a facile processing of polymer foams with high loading of fillers. The corresponding filler dominant lightweight products open the door to a wide range of potential applications to reduce the use of non‐biodegradable plastics.