Biological soil crusts (Biocrusts) are a mixed community which composed of cyanobacteria, moss and lichen in different proportions under natural condition. They significantly affect the soil nutrients. However, the relationship between the soil nutrients of mixed biocrusts and its community structure is unclear, which would hinder the assessment of soil nutrients of mixed biocrusts. Therefore, this study measured the soil organic carbon, total nitrogen, total phosphorus, available phosphorus, ammonium nitrogen and nitrate nitrogen contents of cyanobacteria, moss and mixed biocrusts with different proportions of cyanobacteria and moss, which were 80% Cyanobacteria + 20% Moss, 60% Cyanobacteria + 40% Moss, 40% Cyanobacteria + 60% Moss, and 20% Cyanobacteria + 80% Moss in the Hilly Loess Plateau region. The results showed that (1) the soil organic carbon, total nitrogen, available phosphorus, ammonium nitrogen and nitrate nitrogen contents of moss were significantly higher than those of cyanobacteria by 166.4%, 77.2%, 55.1%, 56.2% and 42.2%, respectively. (2) The contents of organic carbon, total nitrogen, available phosphorus and ammonium nitrogen in mixed biocrusts of cyanobacteria and moss were related to the composition and coverage. The nutrient storage of mixed biocrusts could be predicted by weighting the nutrient content and coverage of single type of biocrusts. (3) The linear functions fitted by the measured values (x) and predicted values (y) of soil organic carbon, total nitrogen, available phosphorus and ammonium nitrogen storage in the mixed biocrusts were y=0.97x, y=0.96x, y=1.18x and y=0.92x, respectively. (4) The effect of mixed biocrusts on soil total phosphorus and nitrate nitrogen contents was not significantly related to the community structure. The biocrusts had little effect on the soil nutrients in the soil layer 0-5 cm. This study reveals the relationship between soil nutrients of mixed biocrusts and community structure, which provides scientific basis for accurately evaluating the effect of mixed biocrusts on soil nutrients under natural conditions.