Xanthan gum is acting as thickener and stabilizer for oil drilling, being an environment friendly and high efficient mud additive, it has an excellent tolerance to a wide range of temperature, pH and salinity. It can extremely increase the mud penetration rate and suspension ability to the drill cuttings. Meanwhile, it can also reduce the pressure loss during drilling, stabilize the well-bore, prevent the damage to oil formation, and improve the efficiency of drilling, work-over and completion.