Abstract: The researcher first did experimental analysis on the basic property of expansive soil, and the compaction test on natural expansive soil and on lime soil with and without fibers. The conclusion is that the lime soil with a small quantity of fibers has little effect on optimum moisture content and the maximum dry density. According to the linear swelling ratio experiment, the researcher concludes that fibers can retain the expansion of the lime. The linear expansion rate decreases remarkably with the increasing of the mixing amount of fibers between 0.05%-0.1%, but slightly between 0.1%-0.2%. With the unconfined compaction test and CBR (California Bearing Ratio), fibers which are reinforced can increase the compressive press of the lime, and the practicability of the above method is evaluated in this paper.