The ceramifiable ethylene-vinyl acetate copolymer（EVA）composite with three dimensional cross-linking structures was prepared by using bis(tertbutylperoxy) diisopropyl benzene (BIPB) as cross-linking agent. The FT-IR spectra and the value of gel content as 99.3% prove that the cross-linking structures are formed. The cross-linking degree in the EVA matrix with silicate glass frits (SGF) and ammonium polyphosphate (APP) as additives was studied. The value of gel content as 98.8% suggests that the SGF and APP show no effect on the cross-linking reaction. Dynamic rheological analysis show that the cross-linked EVA composite has the higher shear viscosity and melt strength than the unmodified EVA composite. Thermogravimetric analysis (TGA) results indicate that the cross-linking modification can improve the thermal stability of the composite. The cross-linked EVA composite exhibits a higher T5% (T5% = 329 ℃) than the unmodified EVA composite (T5% = 311 ℃). The fire resistance test show that the flexural strength of ceramics residues of the cross-linked EVA composite increases with the increase of ablation temperature, the flexural strength is 1.94 times that of the unmodified sample at 1000 ℃, and can well support the mass of the residues in the ablation process，which is also shown by SEM that the surface structures of the residues of the cross-linked EVA composite is more continuous and compact at corresponding temperatures than unmodified sample. Therefore, the cross-linking structures in the matrix improve the fire resistance of the material.