In this paper, the viscosity reduction and modification of xanthan gum were studied to solve the problems of poor dispersion, difficult dissolution and excessive viscosity in aqueous solution. The rheological properties of xanthan gum were improved by screening different modifiers, including heavy metal ions such as Zn2+, Cu2+, Al3+, Fe3+, and acrylamide monomers. The results showed that metal ions could enhance the intermolecular interaction of xanthan gum through complexation, forming a denser network structure, thereby increasing the kinetoplastic ratio. On the other hand, acrylamide grafted copolymers increased molecular weight and flexibility, and significantly improved the rheological properties and rock-carrying capacity of the colloid. The modified xanthan gum exhibited better viscosity stability and rheological properties.