In this study, nest-like microspheres were facilely prepared using halloysite nanotubes (HNTs) as starting material, based on the dehydration reaction between hydroxy groups on the surface of HNTs. The nest-like structure of the obtained HNTs-based nest-like microspheres (HNTs-NMs) is demonstrated by SEM observations. HNTsNMs exhibit desirable dispersibility in water and commonly used polymer matrices, which can be used as reinforcing agents in preparing epoxy resin composite in situ. The incorporation of HNTs-NMs into the epoxy resin gives rise to higher properties in stretching, impact, and toughness than both epoxy resin and equivalent HNTs-reinforced epoxy resin. The development of HNTs as nest-like microspheres affords the reinforcing agent with simultaneously enhanced mechanical properties for the obtained polymer composites. Furthermore, Moanchored HNTs-NMs (Mo-HNTs-NMs) were synthesized and a desirable microwave absorption ability is obtained. The optimal reflection loss is -25.47 dB at 16.91 GHz. When used as reinforcing agent, Mo-HNTs-NMs show a near-equal effect as compared to HNTs-NMs.