Discarded disposable face masks can easily cause environmental pollution, and microbial-induced calcium carbonate precipitation (MICP) technology can lead to soil brittleness. This article attempted to combine discarded disposable face masks with MICP technology by adding the shredded face mask (SFM) with six different percentages (0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% by weight) to ISO standard sand. The test results showed that the optimal content of SFM was 0.2%. Compared with the sand samples without SFM, the water absorption rate decreased by 26.99%, the dry and saturated unconfined compressive strengths (UCS) increased by 145.11% and 252.38%, respectively, and the failure strain increased by 127%, and the calcium carbonate content increased by 20.1%. Meanwhile, 0.2% SFM fiber can form a three-dimensional network structure, which restricts the displacement and deformation of sand particles, improves the brittleness of the sand samples, and enhances the strength of the sand samples. This study provides an effective method for recycling discarded disposable face masks while promoting the application of fiber-reinforced MICP-treated sand in geotechnical engineering.