Mosses and cyanobacteria are multifunctional communities that regulate the eco-hydrological functions of soil and are increasingly recognized as promising, sustainable resources for restoring degraded ecosystems. However, current knowledge regarding the effects of mosses and cyanobacteria on eco-hydrological processes in degraded karst environments remains limited. To provide more insight into this issue, a 14-month field monitoring experiment was conducted to explore the influence of mosses and cyanobacteria on soil moisture dynamics in the top layer under three treatments: Inoculated Hypnum cupressiforme, covered Nostoc commune and bare soil. The results showed that Hypnum cupressiforme and Nostoc commune treatments significantly increased shallow soil moisture by 6.09 %-14.6 % and 1.05 % -10.8 % in the 5 cm soil layer, by 0.34 % -9.6 % and 0.43 % -7.01 % in the 10 cm soil layer, respectively. Compared with bare soil, Hypnum cupressiforme treatment to slow down the rate of soil dehydration was superior to that of Nostoc commune treatment during the drying season; during the wetting season, Hypnum cupressiforme treatment significantly slowed down the loss rate of soil moisture, while Nostoc commune treatment only slowed down the loss rate of soil moisture in 10 cm soil layer, but accelerated the loss of soil moisture in 5 cm soil layer, which may be attributed to the high sensitivity of Nostoc commune to water. The runoff depth of bare soil were 1.55-9.14 times and 3.52-131.41 times than that of Hypnum cupressiforme and Nostoc commune, respectively, which indicated that Hypnum cupressiforme and Nostoc commune play a role in controlling runoff and increasing water infiltration. This study can contribute to the further understanding of the eco-hydrological processes and hydrological simulation of the humid ecosystem