The invention discloses a preparing method for photocatalyst filter materials, which comprises the following steps: firstly, preparing a filter material of a photocatalyst material containing one of titanium dioxide, zinc oxide and tin oxide or the mixture thereof; then, modifying the photocatalyst filter material with silver (Ag), gold (Au), platinum (Pt) or other metals by the photodeposition method. Thereby, the photocatalyst filter material has good photocatalyst catalytic activity and can effectively remove various volatile organic gases, inorganic gases and various polluted gases. The photocatalyst filter material has long life cycle, is not easy to inactivate, and can be washed for reuse.