A composition comprising metal oxide particles having photo-catalytic activity, a solvent-soluble zirconium compound and a solvent. Preferably, the metal oxide particles having photocatalytic activity are titanium oxide particles; the metal oxide particles have an average particle diameter of about 0.005 to 0.3 .mu.m; and the amount of the zirconium compound is in the range of about 3-200 parts by weight, as ZrO.sub.2, per 100 parts by weight of the metal oxide articles. A composite of a film having a photo-catalytic activity with a base material is made by coating the base material with the above composition to form a film, and curing the film on the base material.