The relationship between macroscopic properties of fracturing fluid, molecular microstructure and fracturing fluid proppant carrying capacity was studied through static state proppant settlement experiment, dynamic viscoelastic test, yield stress test, scanning electronic microscope observation. Proppant settlement experiments showed that?a?nonlinear?relationship?existed?between the change of viscosity of fracturing fluid and proppant settling rate, which indicated that viscosity index could not characterize the carrying capacity of fracturing fluid accurately. Dynamic viscoelastic tests showed that the increase of loss modulus was favorable of reducing the rate of proppant settling, while a significant increase of storage modulus which endowed the fluid elasticity maybe the main reason for proppant keeping suspension for a long time in crosslinked fracturing fluid. Fracturing fluid microstructure analysis showed that the fracturing base fluid possessed a disorder, loose, plurilocellate, and mesh-stacked structure, while the crosslinked fracturing fluid possessed a well-distributed, close and the whole-stacked structure, endowing the elasticity of crosslinked fracturing fluid and causing a essence change of fracturing fluid proppant carrying capacity.