Abstract: In order to explore the effect of fiber on the self-healing effect of microbial concrete cracks, polyacrylonitrile fiber was selected and incorporated into microbial concrete. The mechanical properties of microbial concrete after incorporation of fiber, crack permeability and crack residual width during self-healing curing period were tested. The test results show that when the fiber content is 1.5 kg/m3, the splitting tensile strength of the concrete specimen restored to 95.1% of the specimen without microbial carrier. After 28 days, the permeability coefficient of the specimen with an average crack width of 0.43 mm decreased from 3.35×10-5 m/s to 3.40×10-6 m/s, with a decrease of 89.9%. The maximum crack width that can heal is 0.82 mm. The incorporation of fiber into microbial self-healing concrete can effectively improve its crack resistance and enhance the self-healing effect of cracks.