Abstract: The improper disposal of waste masks poses risks to both the ecological environment and human health. This study evaluated the strength characteristics of shield tail slurry solidified soil reinforced with waste mask fibers through unconfined compressive strength tests and splitting tensile strength tests. The effects of fiber content, surface area, and aspect ratio on the compressive and tensile strength of the reinforced solidified soil were analyzed, and the results were compared with those of unreinforced solidified soil. The feasibility of using waste masks as geotechnical reinforcement materials was preliminarily assessed. The results indicate that the incorporation of waste mask fibers not only enhances the compressive and tensile strength of the solidified soil but also improves its residual strength and modifies its plastic behavior. Under the experimental conditions of this study, the compressive strength and tensile strength increased by 32%~178% and 79%~160%, respectively. The optimal reinforcement parameters were determined to be a fiber content of 0.3% and a fiber size of 2 cm×0.25 cm.