The research synthesized bis-(2-methyl quinoline) squarylium cyanine (abbr. QYCD). It was used as dye to enhance the photocatalytic activity of nano-TiO2 in sunlight. Then the photocatalytic process of removal of benzene was investigated indoor air. Results reveal that bis-(2-methyl quinoline)- squarylium cyanine has an intense absorption in the light region of 200nm - 800 nm. The Benzene removal of QYCD-nano-TiO2 complex catalyst at 78h was 97.69%, at the same time it was 36.96% higher as compared with that of nano-TiO2.