Currently, chemical synthetic fibers and wood fibers are commonly used in ready-mix mortar. After surface modification of these chemical synthetic fibers, such as polypropylene staple fiber or PP staple fiber, they will be not only good in dispersion, but also low in the amount added, able to effectively improve the plastic resistance and crack resistance of mortar, meanwhile to have little effect on the mechanical properties of hardened mortar. Wood fibers are smaller in diameter. During the addition of wood fibers, attention should be paid to the increase in its water demand of mortar. At present, in the production of plastering mortar, internal and external wall putty powders, thermal insulation thin facing mortar, grouting mortar, self-leveling flooring mortar, and so on, synthetic fibers and wood fibers have began to be added, while in some antistatic flooring materials, metal fibers and carbon fibers are mainly added. In selection of fibers, consider the following: ① Fibers cannot be too long: Because the mortar layer is usually thin, too long fibers are not conducive to construction. And the particles in mortar are small, so there is no need to use long fibers. ② Fibers cannot be too hard: Too hard fibers are difficult to be spread during plastering and often break the surface into fragments, affecting not only the appearance but also the function of fibers. ③ Fibers should have good dispersibility, evenly dispersed in both the solid-liquid phase and the solid-solid phase. ④ Fibers should be alkali-resistant, and can keep themselves from alkaline corrosion for long in the alkaline environment.