Acid rain has drawn much attention recently. This study was about evaluating the acid-rain-resistant and eco wall which was made of cotton fibers and Tencel fibers. In the experiment, two types of fibers were immersed in stimulated-acid-rain solutions for a week and weighted respectively after drying. This same procedure was repeated weekly three times; meanwhile, the fibers’ pH values were measured daily. The result showed that cotton fibers surpassed Tencel fibers, demonstrating smaller weight losses and positive pH results. The cotton fibers were able to adjust its pH value to 6.8, which provided a suitable environment for plants.