We investigated the physical properties of natural fiber reinforced PLA composites, which were prepared by using PLA films and fibers. The impact, tensile, and dynamic mechanical properties of the composites were observed to examine the reinforcing effect of natural fibers. In addition, numerical analysis was carried out to more clarify the experimental results. The natural fibers/PLA composites shows a good potential for substituting traditional composites such as glass fiber or carbon fiber reinforced composites.