The invention discloses a porcelain tile and a preparation method thereof, and purpose of residue of aluminum extraction from fly ash. The porcelain tile provided by the invention uses residue of aluminum extraction from fly ash as a main raw material. The raw material comprises the following components: 30-45 wt% of residue of aluminum extraction from fly ash, 15-20 wt% of kaolin, 35-45 wt% of feldspar, 0-6 wt% of quartz and 1-3 wt% of talc. The porcelain tile provided by the invention has water absorption less than 0.5 wt% and rupture modulus larger than 35 MPa, and satisfies quality requirements of GB / T4100-2006. The invention uses a solid waste, residue of aluminum extraction from fly ash, in a scientific way, realizes the recycling of waste and expands the source of raw materials for porcelain tile production.