Abstract: With the continuous advancement of oil and gas exploration technology, China’s oil and gas resources development has entered the stage of gradually shifting from shallow wells to deep and ultra-deep wells. This transition has brought about the forefront significant issues regarding rubber stator bushing in screw drilling tools, such as high-temperature thermal aging, and swelling in oil-based drilling fluids. These issues lead to the performance deterioration of drilling tools, thus severely affecting drilling efficiency. Therefore, it is urgent to understand the impact of swelling on the performance of rubber stator bushing at high temperatures. Through high-temperature swelling and aging experiments on rubber materials and subsequent performance testing, Yeoh model was selected as the hyperelastic constitutive model. Finite element models were established using constitutive parameters and swelling equivalent temperatures for different swelling durations. The effects of swelling duration on the inner cavity deformation of the rubber stator bushing mechanical properties, sealing performance, flow area, and hysteretic heating were analyzed. The research results show that with the increasing of swelling duration, the inner cavity deformation is initially increased and then begins to level off; the Von Mises stress and contact stress gradually increase; the flow area gradually decreases and then tends to be stabilized, which is reduced by 12.2 % in case of swelling saturation; the maximum temperature rise due to hysteresis heating gradually increases. This study provides a guidance for the design and application of rubber stator bushing in screw drilling tools under harsh conditions of high-temperature and high-pressure drilling fluids.