In order to improve the properties of xanthan gum（XG），3-chloro-2-hydroxypropyltrimethylammonium chloride and propylene oxide were used as modifiers to etherify XG to obtain cationic xanthan gum（CXG）and cationic hydroxypropyl xanthan gum（HCXG）. The structure of the product was characterized by infrared spectroscopy，nuclear magnetic resonance and X-ray diffraction（XRD）. The rheological properties of XG，CXG and HCXG solutions and their performances as fracturing fluids were studied. The results of infrared，nuclear magnetic and XRD test showed that the cationic etherifying agent and hydroxypropyl group were successfully connected to XG. The prepared HCXG had an average degree of cationic substitution of 0.3175% and a degree of hydroxypropylation of 0.500%. The rheological properties of HCXG solution and the performance as fracturing fluid base fluid were superior to those of CXG and XG solutions. The viscosity of solution after XG modification increased. The apparent viscosity of 0.4% HCXG solution was 6.27 times and 2.27 times larger than that of XG and CXG solutions，respectively. After the modification，the solution strength，yield stress，viscoelasticity，temperature and shear resistance，sand carrying capacity and gel breaking property of XG were all significantly improved. The rheological property of HCXG solution and the performance as fracturing fluid base fluid were good. HCXG solution could be used for fracturing fluid thickener.