A novel mesoporous anatase yttrium-doped TiO₂ nanosheet-array film was prepared via a low-cost, facile and template-free solvothermal method by employing Waste Tricolor Fluorescent Powder (WTFP) as a dopant yttrium source and acetic acid as a mesopore creator. The as-prepared Y–TiO₂ film exhibited large specific surface area, high pore volume and high temperature anatase phase stability. The significant increase of photocatalytic activity was confirmed by the degradation of Methyl Orange (MO) aqueous solution under simulated solar light irradiation. The large enhancement of photocatalytic activity could be due to the synergistic effect of Y-doping and high specific surface area as well as the developed mesoporous structure.