The invention provides a composite fiber material. The composite fiber material comprises an organic fiber carrier and a plurality of functional nanoparticles embedded into the organic fiber carrier. The invention further provides a preparation method of the composite fiber material. The preparation method comprises the following steps: (1) heating the plurality of functional nanoparticles; (2) jetting the plurality of heated functional nanoparticles onto the organic fiber carrier through hot air flow, and melting contact parts of the organic fiber carrier and the plurality of functional nanoparticles so as to embed the plurality of functional nanoparticles into the organic fiber carrier. The composite fiber material takes the organic fiber carrier as a carrier so as to effectively load the functional nanoparticles. In the loading compounding way, the high loading capacity of the functional nanoparticles can be achieved. Meanwhile, the functional nanoparticles are expanded to all scenes to which a flexible fiber carrier can be applied. The composite fiber material can be applied to the fields of sewage purifying treatment, air purifying treatment or antibacterial sterilizing treatment or the like.