Abstract: With the rapid development of rail transit, the noise pollution caused by it has attracted wide attention, and the use of noise barriers to deal with the noise pollution problem is one of the most effective measures at present. The most widely used upright plug-in type resistive noise barrier screen panels are used as the research object in this paper. Based on the equivalent fluid theory of porous material, the relevant sound absorption finite element model is established, and the sound absorption and sound insulation performances of the noise barrier under different opening conditions of the cover plate are calculated. The sound absorption and sound insulation performance are systematically studied, and an optimization scheme of setting air-back cavity without changing the original noise barrier structure is proposed. The effects of the optimization measure on the sound absorption and isolation capacities of the base noise barrier are further analyzed. The results show that when the aperture rate of the open cover plate on the source side is 15%, the sound insulation does not change compared with that without cover plate when the frequency is less than 1 000 Hz, and when the frequency is greater than 1 000 Hz, the sound insulation is better than that without cover plate, generally about 1.5 dB higher. With the increase of the aperture rate, the frequency point where the sound insulation is better than that without cover plate gradually shifts to high frequency, and the advantage gradually decreases. Under the condition that the aperture rate remains unchanged, the smaller aperture size of the front cover plate is more beneficial to improve the sound absorption performance of the barrier. Arranging a certain thickness of air-back cavity after the porous sound-absorbing material can not only improve the sound absorption/ insulation performance to a certain extent, but also save a lot of manufacturing cost of the sound barrier.