In the South of Viet Nam, every year, a large amount of excavated sludge from construction sites has been disposed directly in the final disposal, but the recycling rate of sludge is low. Therefore, in this study, fiber-cement stabilized soil method was applied to recycle sludge in Viet Nam. Moreover, paper, rice straw, rice husk, and cornsilk were used as fiber materials in this method because they are waste materials and easily obtained in Viet Nam. Four kinds of fiber and cement were used to improve sludge and unconfined compression tests were carried out to collect failure strength and strain data. The experiments were performed under 28 mixing conditions. The water, fiber, and cement content were changed to find out which fiber material is the most suitable to modify sludge in Viet Nam. The results showed that rice straw gave the best results to modify sludge by using fiber-cement stabilized method.