The invention discloses an ultraviolet resistant treatment agent based on disperse dye modification. The general structural formula of the ultraviolet resistant treatment agent is as shown in the specification. Stretching vibration peaks representing Si-O-Si and Si-C respectively appear at 588cm<1>, 1109cm<1> and 782cm<1> positions of an infrared absorption spectrum of the ultraviolet resistant treatment agent, stretching and bending vibration peaks representing -CH2-CH2-, -CH2-CH2-CH2- or -CH2-CH2-CH2-CH2 respectively appear at 3068cm<1>, 2962cm<1> and 1460cm<1> positions of the infrared absorption spectrum of the ultraviolet resistant treatment agent, a vibration peak representing silicon atoms in a POSS (polyhedral oligomeric silsesquioxane) structure appears at a -109.63ppm position of <29>Si NMR (nuclear magnetic resonance) spectrogram, and absorption peaks appear below 300nm wavelength of ultraviolet-visible absorption spectra of solution. The invention further discloses a preparation method of the ultraviolet resistant treatment agent. The ultraviolet resistant treatment agent can be firmly inlaid into a shallow fiber layer by the aid of dye molecules by a high-temperature high-pressure treatment method and fixed onto fibers, durable ultraviolet resistant functions are achieved, and the synthetic fibers can be simultaneously dyed.