The invention discloses a preparation method of a low-temperature plasma modified catalytic fiber filter material. The method comprises the following steps: 1) weighing polyurethane as a solute, and preparing a solution by using a dimethylformamide solution as a solvent; 2) adding a tetraethylammonium bromide powder into the obtained solution to obtain a mixed solution; 3) adding a catalyst precursor into the mixed solution, and performing stirring to obtain an electrostatic spinning solution; 4) carrying out electrostatic spinning on the electrostatic spinning solution, and collecting spun yarns to obtain a nanofiber film; 5) putting the nanofiber film in a low-temperature plasma modification device, introducing argon, carrying out plasma modification, and cooling the obtained film to room temperature to obtain a low-temperature plasma modified catalytic fiber film; and 6) coating and packaging the low-temperature plasma modified catalytic fiber film to obtain the low-temperature plasma modified catalytic fiber filter material. The method which adopts preparation of the fiber filtration material by combining the electrostatic spinning with the low-temperature plasma modification process as the innovation point has the advantages of wide material sources, easiness in process operation, good product processability, good market competitiveness and good promotion values.