The common railway subgrade filling and 0.3%polypropylene fiber reinforced subgrade filling were respectively adopted to build small-size laboratory subgrades.The effect of the two kinds of fillings on stress distribution and settlement deformation of the model subgrades under multi-stage external loads was analyzed.Then the feasibility and validity of using fiber reinforcement as a settlement control technology were discussed.The test results shows that the diffusion rate of stress in the fiber reinforced model subgrade accelerates comparing with that in the unreinforced model subgrade.The settlement law of the two models is similar when the external loading reaches to 100 kPa.The settlement at different depths of the subgrade model increases nonlinearly with the external loading.An inflection point appears on the settlement curve for the fiber reinforced subgrade when the external loading comes up to 200 kPa.The settlement curve demonstrates a shape of elongated"s".The total settlements at top of the fiber reinforced subgrade reduce 30.3% and 35.4% in contrast to the common subgrade under the external loadings of100 kPa and 200 kPa respectively.The fiber reinforcement is more efficient in settlement control under heavy external loading and large deformation conditions.