Nano-TiO_2 as a photocatalytic material is applied widely in many fields.At present it has become a hot spot of studying nanosized TiO_2 to improve its photocatalytic activety and increase the field of its application.This paper summerises the advance made in improving the photocatalytic property of nano-TiO_2 by adulterating-modifing and the fields of application of modified TiO_2.