Commercially available mixed crystal TiO_2( P25) was used as a modification target to prepare N-doped modified P25( N-P25) with visible light activity by hydrothermal method,and apply it to wallpaper. The effects of N-Ti molar ratio,hydrothermal reaction temperature and time on the structure and light catalytic performance were investigated. The results show that the modified P25 also has the mixed crystal structure of anatase phase and rutile phase,and the visible light absorption is improved. Under the co...