The present invention relates to the fracturing field, and discloses a water solution, a clean fracturing fluid, and a method for fracturing reservoir. The water solution contains organic acid amidopropyl dimethylamine, an additive, and water, wherein, the additive is at least one of salicylate, cis-butenedioic acid, o-phthalic acid, dodecyl sulfonate, p-toluene sulfonate, and benzoate. The water solution has high carbon dioxide response performance, a clean fracturing fluid that contains the water solution has superior cyclic utilization performance, and the fracturing fluid can solve the problems of conventional fracturing fluids used in fracturing stimulation of oil and gas reservoirs, including incomplete gel breaking, severe damages to the reservoir, and severe contamination of flow-back fluid, etc.