Abstract: To solve the problems of water shortage in fracturing operation and fracturing outlet liquid handling difficulty, the borate dissociation equilibrium principle is controlled by pH value to change the crosslinked state of guar gum fracturing fluid for the degradability of gel breaking under acidic condition. The molecular structure of guar gum is not damaged, so it can be crosslinked again. This paper used the biodegradation technology to degrade guar gum, and controlled the molecular weight of the guar gum by controlling the degradation conditions to control the degree of degradation of guar gum, eventually a low molecular crosslinked guar gum have been developed with molecular weight from 30×10⁴ to 50×10⁴ under the condition of borate. The viscosity of aqueous solution of the low molecular guar gum was low, and the water insoluble content was less than or equal to 4%. Taking a solid acid as a capsule core, a polymer being gradually dissolved in the water as the capsule dressing, a capsule breaker have been prepared using the method of air suspension film. The capsule breaker is not acidic on the ground for ensuring the fracturing fluid to be crosslinked well, and under formation temperature and pressure conditions the capsule breaker can gradually release the solid acid for the fracturing fluid degradability gel breaking. Taking the low molecular guar gum as the thickening agent, the capsule breaker parceling solid acid as the breaker, a recycled low molecular guar gum fracturing fluid has been developed. The fracturing fluid has been widely used in Sichuan Xu Jiahe reservoir reconstruction, and a lot of fracturing outlet liquids have been recycled. The effect of energy conservation and emissions reduction is remarkable.