The invention discloses a low-damage and ultralow-concentration guar gum fracturing fluid system, a preparation method and an application of the guar gum fracturing fluid system and belongs to the technical field of reservoir reforming for oil-gas field development. In order to solve the problems that the existing conventional fracturing fluid systems hardly give attention to the lowering of concentration of a thickener, the prolonging of crosslinking time, the improving of gel strength and gelout capability and being environmentally friendly, a SITAR-11 powerful delayed crosslinker is selected, so that formed gel is endowed with a relatively high delayed crosslinking effect while heat resistance, shearing resistance and solid carrying capacity for the formed gel are guaranteed, and the concentration of the thickener is greatly lowered; and on one hand, the reduction of cost and the increase of economic benefit are facilitated, and on the other hand, the amount of gelout residues is reduced after the concentration of the thickener is lowered. Further, FANTA-05 and FANTA-06fracturing gelout enzymes, which are thorough in gelout and controllable in gelout time, and a ZITHE-34 efficient discharge aiding agent are added in a matched manner, so that the fracturing fluid system, which has a delayed crosslinking effect, is high in heat resistance and salt tolerance, excellent in solid carrying behavior, controllable in gelout time and thorough in gelout and is green, environmentally friendly and efficient, can be formed.