In Shandong province, silt is widely distributed in the Yellow River flooding area.In the case of shortage of railway roadbed filling material, reinforced silt is commonly used as an alternative.In this study, the silt in the Yellow River floodplain area was reinforced by using nano-silica and lime as modifiers.The strength of the silt was measured by compaction test and unconfined compressive strength tests.It was found that although the strength of the silt was significantly improved, the material also showed some characteristics of brittleness.In order to overcome this disadvantage, polypropylene fibers were added to silt and then, the influences of fiber content and length on the strength and brittleness of the silt were studied through a series of experiments.The optimum fiber content and the optimum fiber content were determined.The results show that the brittleness and compressive and shear strength of the silt can be improved by adding fibers; and when the content of fibers is 0.4% and the length of fibers is 2 cm, the improvement effect is the best.