The invention discloses a plant composite nanometer graphene photocatalytic deodorant, and a preparation method thereof. The preparation method comprises following steps: S1, a material A is preparedfor further using, wherein the material A contains plantain seed, bamboo leaf, tea, ginger, camphor tree leaf, sophora japonica leaf, and dried cortex cinnamomil; S2, a material B is prepared for further using, wherein the material B contains argy wormwood, lemon, Chinese ilex, pine needle, shaddock peel, and mint peel; S3, a material C is prepared for further using, wherein the material C contains a graphene modified nanometer titanium dioxide heterostructure composite photocatalyst and graphene; S4, a material D is prepared for further using; and S5, by weight, 40% of the material A, 40% ofthe material B, 14% of the material C, and 0.1% of the material D are mixed, an obtained mixture is introduced into a magnetic stirrer, 5.9% of pyroligneous vinegar is introduced into the magnetic stirrer, stirring is carried out for 2 to 5h at 40 to -60 DEG C so as to obtain a finished product. The plant composite nanometer graphene photocatalytic deodorant is simple to prepare; cost is low; deodorizing effect is excellent; and the spraying area of the plant composite nanometer graphene photocatalytic deodorant on an object with a certain area is larger.