An organic boron crosslinkerwas synthesized by the reaction between polyamine com-pound(diethylenetriamine、1,4,7,10,13-pentaazatridecane、polyethylene-polyamines、polyethylenimine-600) and boric acid ester. Due to several boron-based crosslinking sites in this crosslinker, the amount of thickening agent used in fracturing fluid was reduced and the heat re-sistance of fracturing fluid was also enhanced. The structures of different crosslinkerswere charac-terized by FTIR 、1H-NMR and 11B-NMR, and the reaction mechanisms were discussed. Several factors including the type of polyamine compounds, the ratio between two raw chemicals, reaction temperature and time were studied.The results show that when the mass ratio of borate esterto poly-ethene polyaminewas 3:2, reaction time was 4 h, reaction temperature was 150℃, the product with the best performance was obtained and named as BNX-1. The heat and shear resistance, gel-breaking performance and static fluid-loss performance of the BNX-1 based fracturing fluid were studied. Af-ter being sheared at a shear rate of 170 s-1 for 120 min under 140℃, the fracturing fluid (guar gum 0.35%, crosslinking ratio 100:0.4) could maintain the viscosity up to 122 mPa·s. However, the vis-cosity of an industrial crosslinker (TCB-1) based system (guar gum 0.5%, cross-linking ratio 100:0.5) was 98 mPa·s via the same measurement.