Environment-friendly green composites were developed by combining a biodegradable resin with curaua fibers. The composites were fabricated by three different methods, i.e. direct, pre-forming and prepreg sheets methods. Mechanical properties of composites fabricated by all three methods were evaluated through tensile test. Moreover, green composites reinforced by fibers treated with high concentration alkali solution were fabricated by pre-forming and prepreg sheets methods. The results showed that fracture strain of alkali-treated fiber composites increased twice to three times larger than that of untreated-fiber composites. Finally, effect of cyclic load application on tensile strength of curaua single fibers was investigated.