Abstract: Palygorskite/carbon (PG/C) composites were synthesized via a hydrothermal route at 220℃ for 24 h using palygorskite and cellulose (PG) as raw materials. The obtained nano PG/C composites were introduced into the carbon/carbon (C/C) composites during the impregnation-carbonization process. Thus the C/C-ceramic/C composites were in-situ prepared by one-step hot pressing method. The mechanical and antioxidant properties were studied for C/C composites using PG/C as additives. The results show that the PG/C converts to enstatite/C during hot pressing process. The resulted enstatite/C enhances the mechanical properties of C/C composites by filling and bridging, and the nano C layer loading on the surface of enstatite ceramic avoids weak-binding between ceramic phase and C matrix. Along with the decrease of nano C loading on surface of PG/C, the strength of C/C increases gradually. The PG/C with C content of 13% exhibits flexural strength of 263 MPa and elastic modulus of 47 GPa. Compared to that of C/C without additive, the values increases by 45% and 42% respectively. Compared to that of C/C introduced PG as additive, the value increases by 16% and 27% respectively. Also, the antioxidant properties of C/C improve due to the doped PG/C. The mass loss reduces by 12%-18% at 1000℃.