[Objective] The effects of microorganisms and algae on the recovery of biocrusts in the field were studied and the biocrusts protection technology of high and steep loess slopes was optimized in order to provide new ideas and methods for regional ecological restoration.[Methods] The effects of algae(chlorella+diatom mixed algae) and functional microorganisms(Bacillus licheniformis, Bacillus megaterium) on the development of artificially restored biocrusts were studied by complete experiments.[Results] ① There were significant difference in development among different treatments, the median biocrust coverage of algae+Bacillus megaterium was the largest, with a mean value of 61.41%; the median biocrust thickness of Bacillus licheniformis was the largest, with a mean value of 2.58 mm; the median height of moss plant treated with only 3 g algae was the highest, with a mean value of 2.67 mm. ② Algae treatment could explained the difference of biocrusts coverage, thickness and plant height among different sample squares significantly(p<0.05) under different addition levels (0,1 or 3 g/m²), and the suitable addition amount was 2~3 g/m². ③ The functional microorganisms showed little effects on the biocrusts coverage, thickness and plant height of moss (p=0.91/0.93/0.49) and it showed no significant interaction with algae.[Conclusion] Artificial restoration of biocrusts on 45° slope is feasible. Spraying the algae solution on the slope with suitable environment, inoculating the gametophytic fragments of moss and carrying out the restoration of the biocrusts, can effectively construct a well-developed biocrusts protective layer with a certain coverage and thickness.