Silanized graphene oxide (SiGO) was synthesized and characterized using KH570 as a modifier on graphene oxide (GO). Subsequently, high performance silanized graphene oxide/cardanol based benzoxazine (C-fa)-bismaleimide (BMI) resin composites (SiGO/C-fa/BMI) were prepared by blending and step thermal curing. The reaction and dispersion of SiGO in C-fa/BMI matrix were studied by FTIR and XRD. The effects of SiGO on the thermal and mechanical properties of the SiGO/C-fa/BMI composites were investigated. The results shown that SiGO has good dispersity in CFa-BMI matrix. The thermal decomposition temperature and char yield of SiGO/C-fa/BMI composites was improved markedly. Comparing with that of neat C-fa/BMI resin, the young's modulus and tensile strength of SiGO0.5/C-fa/BMI composite increased by 110.8% and 142.0%. The water absorption of SiGO/C-fa/BMI composites also decreased significantly. The great improvement in thermal and mechanical properties of SiGO/C-fa/BMI composites make them as a potential alternative high performance resin composite candidate in aerospace and electronic area.