The invention provides a fracturing fluid suitable for hydraulic fracturing sand adding operation of under a coal mine. The fracturing fluid is composed of the following components: a thickening agent, a cross-linking agent, an anti-swelling agent, a gel breaker and water, wherein the mass volume ratio of the thickening agent to the cross-linking agent to the anti-swelling agent to the gel breakerto water is (0.2-0.35 g): (0.2-0.35 g): (0.5-2.0 g): (0.05-0.2 g): 100L. The preparation method comprises the following steps: (1) building a liquid preparation tank; (2) adding water into the liquidpreparation tank; (3) adding the thickening agent into the liquid preparation tank, and carrying out stirring while stirring; (4) adding the anti-swelling agent into the mixed solution, and carryingout stirring; and (5) adding the cross-linking agent and the gel breaker to the mixed solution in the step (4) to obtain the fracturing fluid. The fracturing fluid prepared by the method disclosed bythe invention has good sand suspension performance, the anti-swelling rate and the content of the gel breaker residue liquid are low, and thus the fracturing fluid is suitable for the environment of hydraulic fracturing sand adding operation under a coal mine.