Abstract: Bryophytes are "pioneer" plants in harsh environments, playing an irreplaceable role in soil and water conservation and community succession. And bryophytes are also able to improve the ecological environment of deserts. To examine the soil and water conservation ability of mosses in rocky desertified areas, biomasses, saturated water absorption rate and evaporation rate of various mosses in the karst area were measured. And mosses dominant in the Guiyang Karst Park were separated from the crust soil and oven dried for measurement of biomass. Saturated water absorption of the mosses were measured after the mosses got fully saturated with water. And evaporation rates of the mosses were measured at 20, 40, 60, 90 min and 2, 3, 4, 8, 12, 24, 28, 32, 36 and 40 h. Results show that Hyophila stenophylla was the lowest in biomass(6.92±0.75) g·m^-2, while Brachymenium exile the highest(62.64±2.45) g·m^-2; Hyophila stenophylla was the lowest(123.61±1.21) g·m^-2 and Brachymenium exile the highest(689.89±6.89) g·m^-2 in saturated water absorptions too; and Brachymenium leptophyllum was the lowest(524.98±3.65)% and Erythrodontium julaceum the highest(1633.30±7.48)% in saturated water absorption rate. Evaporation rates of all the mosses exhibited a gradually decreasing trend within the period of 0-30 h and approached to 0 g·kg^-1·h^-1 at the end. Barbula grescens was more likely to lose water, whereas Brachythecium plumosum is less likely than all the others. In view of the great differences in water retention capacity between different species of mosses, Braunia delavayi and Brachymenium exile are held to be the most suitable pioneers in remedying rocky desertified lands.