the same optimal cement content of 8% and the fiber content of 1.5%, the strength of the cementeclay improved by fiber bundles were relatively lower than the specimens added with polypropylene fibers, but the difference is less than 5%. When fiber length increased, the strength of polypropylene fiber-reinforced cement soil also grew, with the growth rate accelerating. The same results came again as for cementeclay improved by fiber bundles. It indicates that long fibers were more helpful rather than short fibers in the length range we studied.