The invention discloses a self-repairing hydrophobic cotton fabric finishing method. The self-repairing hydrophobic cotton fabric finishing method comprises the following steps: mechanically stirring and mixing tetraethoxysilane, deionized water and alcohol till a solution is clarified, wherein the volume ratio of the tetraethoxysilane to the deionized water to the alcohol is 1:2:2; regulating the pH value of the solution to be 3-4 by utilizing glacial acetic acid, and diluting the solution by water to obtain a stably dispersed silica sol finishing agent; adding a fluoro-acrylate polymer to a diluted ammonia solution to obtain a mixed solution, adding an oxidant to stir till the solution is clarified, and adding a penetrating agent to obtain a fluoride-containing polyacrylic acid finishing agent; padding refined cotton fabric by utilizing the silica sol finishing agent, boiling the fabric in water, drying, padding the fabric by utilizing the fluoride-containing polyacrylic acid finishing agent, pre-drying the fabric for 1-5 minutes at 60-90 DEG C, and baking for 1-2 minutes at 130-170 DEG C to obtain the self-repairing hydrophobic cotton fabric. The self-repairing hydrophobic cotton fabric finishing method has the advantages of being convenient to operate, simple in process and good in operability, thereby being suitable for various cotton fabrics; the prepared hydrophobic cotton fabric has great durability, a self-repairing function and an excellent application prospect.