The invention discloses an application of polyacrylic acid modified based on pyrimidone to preparation of a self-repair material. 2-ureido-4[1H]-pyrimidinone with an isocyanate group and polyacrylic acid react to obtain polyacrylic acid with 2-ureido-4[1H]-pyrimidinone. Then, the polyacrylic acid with 2-ureido-4[1H]-pyrimidinone is mixed with tetracarboxylazobenzene, then, suction filtration is performed, a film is formed by a filtrate obtained after suction filtration, and scratches on the film gradually disappear under the irradiation of ultraviolet light.