The product is a high-molecular-weight, anionic liquid polymer. It has a strong capability of inhibiting the dispersion of clay and debris, and can significantly improve the inhibition of drilling fluid, which is helpful for solid control and the stabilization of borehole. Besides, the product is compatible with anionic and amphoteric agent. It can be used in WBM drilling fluids system with various relative densities, ranging from fresh water, salt water to saturated salty water.