The work aims to investigate the effect on the crosslinking degree, mechanical property and thermal conductivity of the EVA film after the addition of SiC inorganic filler into the ethylene-vinyl acetate (EVA) copolymer film. With the SiC inorganic filler added into EVA, the organic macromolecules of continuous phase in the whole system and the inorganic filler of dispersed phase were blended. Then, the films of uniform thickness were obtained by extrusion casting and forming. The tensile strength and elongation at break of EVA composite film decreased with the increase of SiC content. The crosslinking degree slightly increased with the increase of SiC content, and the balance was finally achieved. The peel strength increased first and then decreased. When SiC surface was treated by different coupling agents, the thermal conductivity of EVA thermal conductive composite films was different. When SiC surface was treated by one coupling agent, there was still difference between the SiC particle size and the thermal conductivity of EVA thermal conductive composite films. The size, additive amount and surface treatment of added SiC have great impact on mechanical property and crosslinking degree of EVA thermal conductive composite films.