The ever‐increasing consumption of fossil energy highlights the urgent need to develop technologies to ensure the efficient drilling and exploration of oil and gas resources mainly distributed in deep and ultra‐deep layers. The complex geological conditions in deep formations with the feature of high temperature, high pressure and high salinity result in some very high requirements for the performance of drilling fluids. Various additives were demonstrated to decide the physicochemical properties and functional characteristics of water‐based drilling fluids that have been widely used to drill over 80% of wells. As one of the most crucial and most widely used additives in water‐based drilling fluids, various polymeric filtrate reducers play an important role in minimizing fluid loss, maintaining wellbore stability, ensuring drilling safety and efficiency as well as avoiding formation damage. Herein we comprehensively summarized the design, preparation and applications of polymer‐based filtrate reducers for fluid loss control in drilling operation. The spotlight is centered on the design strategies and structure‐property‐performance relationships of polymeric filtrate reducers to minimize fluid loss under high temperature, high pressure, and high salinity conditions in the deep formation. Future perspectives for achieving excellent comprehensive performance are also discussed to motivate new strategies and technologies to design and develop high‐performance water‐based drilling fluids with optimal rheological and filtration properties.This article is protected by copyright. All rights reserved