In this study, the intercalated hydrotalcite (HT)/epoxy (EP) nanocomposites containing red phosphorous (RP) (HT-RP/EP) were prepared by in-situ polymerization. Firstly, low-molecular-weight polyamide 6 (PA6)/HT nanocomposite was prepared in the presence of organ-hydrotalcite with alanine as an initiator at 150°C. And then, PA6/HT composite and a certain amount of RP incorporated into epoxy resin in the presence of curing agent (polyamide 650) and HT-RP/EP nanocomposite was prepared successfully. Finally, the micro-structure and flame resistance were characterized by scan electron microscope (SEM) and vertical burning method, respectively. The results showed that HT was dispersed in the epoxy matrix evenly. HT-RP/EP nanocomposites showed significant flame resistance. When the content of both of HT and RP was 5%, the flame resistance achieved FV-0 level.