The invention belongs to the technical field of electric conduction composites, and particularly relates to a cassava residue/PE two-phase electric conduction composite and a preparation method thereof. The cassava residue/PE two-phase electric conduction composite is characterized by being prepared from, by weight, 10-20 parts of electric conduction filler, 10-20 parts of cassava residues and 60-80 parts of PE. The cassava residue/PE two-phase electric conduction composite has the advantages of being small in weight, easy to machine, resistant to wear and corrosion and adjustable in electrical resistivity within a large area. According to the method, through the effect of mechanical ball milling, the electric conduction filler can be well dispersed in cassava residues and a PE base body, the electric conduction percolation threshold value is low, the process is simple, and the cassava residue/PE two-phase electric conduction composite and the preparation method are green and environmentally friendly.