The invention relates to the waterproof processing and finishing technology, in particular to a waterproof antibacterial fabric finishing agent and an application thereof. The waterproof antibacterialfabric finishing agent is composed of the following components by weight parts of: 30 to 45 parts of acrylate copolymer, 5 to 10 parts of silica solution, 1 to 8 parts of long-acting antibacterial agent, 1 to 5 parts of dispersant, and 40 to 60 parts of water. In the invention, through adopting the compounded antibacterial agent components, the dispersion and stability of the long-acting antibacterial agent are improved, and at the same time, the long-acting antibacterial effect of the waterproof antibacterial fabric finishing agent is significantly improved. In addition, the waterproof antibacterial fabric finishing agent disclosed by the invention does not contain PFOS(perfluorooctane sulfonate) and PFOA(perfluorooctanoic acid), which is easily biodegraded, has no bioaccumulative properties, is less harmful to the human body, and is a relatively safe and environmentally friendly product.