Abstract: To control the filtration of drilling fluid under high temperature and high pressure conditions is critical for ensuring the safe and successful drilling. Aiming at the problem that it is difficult to achieve a balance between the environmental protection property and the high temperature filtration performance for conventional filtration reducers, the environment-friendly β-cyclodextrin polymer (β-CDP)microspheres were synthesized with inverse emulsion polymerization method using β-cyclodextrin as the monomer and epichlorohydrin as the crosslinking agent. This paper evaluates the API filtration properties after hot rolling at various temperatures and high-temperature and high-pressure filtration properties after hot rolling at 200℃, which were compared with those of some typical high temperature resistant filtration reducers, and also systematically explores the underlying mechanism of filtration control. The research indicates that when the temperature is below 160℃, β-CDP microspheres exhibit excellent filtration control properties. When the temperature is above 160℃, the filtration control properties will be further improved with the increasing temperature. After hot rolling at 240℃, the microspheres still have prominent filtration control properties, and obviously different characteristics from conventional filtration reducers. When the temperature is below 160℃, the filtration loss is mainly reduced by swelling after water absorption, increasing the compressibility of filter cake, and improving the dispersion stability of clay particles by β-CDP microspheres. When the temperature is above 160℃, hydrothermal reaction occurs in β-CDP microspheres, thus producing micro-nano carbon spheres by degradation. Then, nano composites are formed through interaction of micro-nano carbon spheres and clay particles, which can fill in the micro-nano pores of filter cake and effectively reduce the permeability of filter cake. The temperature response behavior of β-CDP microspheres can change the disadvantage that additives are destroyed under high temperature into the favorable conditions for filtration control.