In order to reveal the effect of biological soil crusts on process of soil and water loss on the slope after the implementation of ecological restoration project in typical red soil region under rainstorm, simulated rainstorm experiments and indoor experiments were conducted. In this research, the soil physical properties, hydrodynamic characteristics, runoff and sediment yield processes of slopes with different biological soil crusts coverages (0, 20%, 40%, 60% and 80%) were explored. The results showed that: (1) Under different coverages of biological soil crusts, the soil cohesion of red soil slope increased by 13.26% on average, while the soil bulk density and penetration resistance decreased by 8.97% and 61.51% on average, respectively, indicating that biological soil crusts effectively enhanced soil stability and soil anti-erodibility in red soil area. (2) Compared with the control slope, biological soil crusts effectively improved the flow pattern of slope, and the values of runoff shear stress ranged from 0.08 to 0.12. The water flow power and section unit energy reduced by 12.22%~78.89% and 8.32%~53.15%, respectively, and the slope resistance coefficient increased by 1.09~1.50 times. (3) The benefits of runoff reduction and sediment reduction on the slope surface of each biological crust coverage were between 12.50% and 78.76%, 17.03% and 94.31%, respectively, in which the soil erosion intensity of the slope with high coverage (80%) was the lowest. The results provided theoretical basis and practical references for effective prevention and control of soil and water loss on slope in red soil area.