In order to improve the rheological and drag reduction properties of xanthan gum（XG），carboxymethyl xanthan gum（CMXG） was synthesized by XG and etherifying agent （sodium chloroacetate）. The rheological properties （shear thinning，viscoelasticity and thixotropy），temperature and shear resistance and drag reduction property of CMXG solution were studied. The results showed that the viscosity of CMXG increased significantly comparing with XG. The viscosity of 6 g/L CMXG solution was 1.56 times more than that of 6 g/L XG solution. The storage modulus，loss modulus，thixotropy and temperature resistance of CMXG solution were greater than those of XG solution. XG and CMXG solutions had shear thinning properties，and the change curve of viscosity with shear rate could be characterized by Cross model. The drag reduction rate of CMXG solution in smooth tube increased with increasing concentration and flow rate. The maximum drag reduction rate of 1 g/L CMXG solution reached 64.3%，and the drag reduction effect was better than that of XG.