The invention relates to an ink slab comprising two components A and B, wherein the component A includes, by weight percentage, 65-70% of PC plastic or ABS plastic, 25-35% of glass fiber and 2% of coupling agent; the component B includes, by weight percentage, 65-65% of filler, 25-35% of PP plastic or PVC plastic, 1.5-2.5% of EVA plastic, 1-2% of white oil, 2% of coupling agent, 4-5% of black color masterbatch and 0-0.5% of toner. The components A and B are respectively mixed, extruded and granulated. During the forming, the components A and B are evenly mixed at a weight ratio of 1:1.5-2.0, and then the mixture is sent into a conventional injection molding machine for injection molding. The ink slab formula is unique, a forming process is mature and simple, and the finished product not only has plastic characteristics, but also has light weight and resistance to water and cracking and keeps quality of a conventional ink slab of grinding an ink ingot, generating fine and uniform ink, accommodating ink, enabling a user to dip a writing brush in the ink and being lasting and resistant to drying. The ink slab is especially suitable for students, as well as outdoor sketching.