Electrosorption has a selective removal effect on the tiny inferior solid phase in the waste water-based drilling fluid, so the performance and the reuse rate of drilling fluids after treatment can be effectively improved. However, such a mechanism has not yet been clarified. In view of this, the experimental materials were characterized using laser particle size analyzer, environmental scanning electron microscope, specific surface and porosity analyzer and X-ray diffractometer, and in combination with the features of waste drilling fluids, laboratory studies were carried out on the main force of solid particle adsorption, adsorption range and selectivity of solid particles by electrosorption, adsorption effect of surface charge on electrode plate. The following findings were obtained. (1) Solid phase particle adsorption mainly relies on the electric field force while the effect of the surface properties of the plate material itself is limited on the adsorption of solid phase particles in waste drilling fluids. (2) When the plate material is in the waste drilling fluids, the surface naturally carrying with a negative charge will not affect the treatment effect of electrosorption. (3) Electrosorption has a good adsorption effect on such drill cuttings with particle size less than 10 μm in waste drilling fluids, but not on those solid particles less than 0.1 μm. No difference was found in mineral types and components of the solid-phase particles separated either from the pre-treatment or from the electrosorption treatment of the waste drilling fluids, which proves that electrosorption has no selectivity for the type of solid particles. In conclusion,  electrosorption recycled waste water based drilling fluids is realized by the interaction of electrosorption and weak electrolysis reaction. The macromolecular polymer in the waste drilling fluids is partially oxidized and broken by the electrode plate to capture, adhere, and coat the suspended solid phase particles, and interacted with the weak electrolytic reaction, thereby reducing the content and viscosity of inferior solid phase.