Abstract: Reinforced soil has been widely used in strengthening soft soil foundation, slope, retaining wall and other projects, in which fiber reinforced soil, as a new composite material, has attracted much attention because of its relatively homogeneous and approximately isotropic properties. In order to study the influence of wave-shape polypropylene fiber on the mechanical properties of sandy clayey purple soil, the unconfined compression and triaxial compression test were carried out by controlling the fiber content (0.2%, 0.3%, 0.4%) and length (20, 30, 40 mm). The test results showed that the unconfined compressive strength of reinforced soil increased first and then decreased with the increase of wave-shape fiber content, and the unconfined compressive strength and residual strength reached the maximum when the fiber content was 0.3%. Fiber length had an effect on the unconfined compressive strength of reinforced soil. When the fiber length was greater than 20 mm, it would increase the unconfined compressive strength, but at the same time, it would also weaken the failure toughness. With the increase of fiber content and length, the cohesion of the sample increased and the internal friction angle decreased.