Strengthening the exploration and development of oil and gas resources is an important measure to ensure people 's livelihood and energy strategic security. However, with the increase of well depth and the complexity of reservoirs, in the face of extreme environments such as high temperature and high salinity, drilling fluid is easy to fail, resulting in increased filtration volume and wellbore instability. Therefore, it is of great significance to develop an efficient treatment agent that takes into account both temperature and salt resistance to ensure the smooth drilling of deep oil and gas. Based on the structure-activity relationship of polymer molecules, a tackifying-filtrate reducer PTF-1 with salt response characteristics was developed by introducing functional monomers. The structure was characterized by infrared spectroscopy and thermogravimetric analysis. Combined with drilling fluid performance evaluation, sedimentation stability analysis, mud cake morphology characterization and Zeta potential test, the mechanism of PTF-1 filtrate reducer in water-based drilling fluid was comprehensively studied. The results show that the pyrolysis temperature of PTF-1 is greater than 300 °C. After aging at 180 °C/16 h, adding 2 % PTF-1 can increase the apparent viscosity of bentonite-based slurry and saturated brine-based slurry by 980 % and 400 % and the API fluid loss decreased by 70.77 % and 85.92 %, respectively. At a dosage of 2wt%, the FLHTHP is only 25mL. PTF-1 is tightly adsorbed on the surface of clay particles through hydrogen bonding, electrostatic, chemical bonding and hydrophobic association to maintain the stable dispersion of drilling fluid system and optimize the quality of mud cake. In addition, PTF-1 cooperates with salt to further achieve excellent fluid loss reduction effect.