In order to improve the temperature resistance of guar gum fracturing fluid and adapt to the development of complex special reservoirs such as deep layer，a nano-silica hybridized fracturing fluid was developed by using nano-silica and guar gum，and the gel was prepared by adding sodium tetraborate crosslinker to fracturing fluid. The effect of mass fraction of nano-silica and crosslinking ratio on the apparent viscosity of gel was studied，and the temperature resistance，viscoelasticity and mechanical property of fracturing fluid gel were investigated. The results showed that it had a big influence of mass fraction of nano-silica and crosslinking ratio on the apparent viscosity of fracturing fluid gel. The nano-silica hybridized fracturing fluid gel which contained 0.3% guar gum，3000 mg/L nano-silica and 0.2∶100 crosslinking ratio（mass ratio of sodium tetraborate to base fluid）showed good temperature and shear resistance. It’s viscosity was 150 mPa·s after shearing 60 min at 170 s^-1 and 90℃，which increased 60 mPa·s comparing with pristine guar gum. The network structure of guar gum fracturing fluid gel was enhanced by nano-silica owe to the good dispersion，increased elasticity and tensile strength of fracturing fluid. Compared with that of pristine guar gum，the elastic modulus of nano-silica hybridized fracturing fluid increased 45% and the tensile force increased 4 N under 10 mm deformation.Nano-silica hybridized fracturing fluid could be used in the fracturing development of complex reservoirs.