Abstract: To implement the national plan of treating more than 50% of treatable desertified land by 2020 and all treatable desertified land by 2050, this experiment focused on aeolian sandy soil in Hotan Prefecture. Six treatments were established by adding different amounts and ratios of Chlorella and Actinomycetes (algae-bacteria agent) to the soil: Control (CK), 2 g Chlorella powder per kg of soil (C1), 4 g Chlorella powder per kg of soil (C2), 4 g Actinomycetes agent per kg of soil (ACK), 4 g actinomycetes agent per kg of soil + 2 g Chlorella powder per kg of soil (AC1), and 4 g actinomycetes agent per kg of soil + 4 g Chlorella powder per kg of soil (AC2). The soil samples were incubated in the dark for 40 days, during which changes in soil pH, organic matter, total nitrogen, NH₄⁺-N, NO₃⁻-N, and other indicators were monitored. After the incubation, soil infiltration characteristics were analyzed through one-dimensional vertical infiltration tests. The results indicated: 1) Compared with CK, the pH values of the soils in treatments C1, C2, and AC1 decreased by 0.443, 0.570, and 0.553, respectively, after 40 days, approaching neutrality (pH 6.5～7.5). The combined application of algae and bacteria buffered pH changes. 2)Compared with CK, the soil organic matter content in treatment C2 increased by 37.69% (P<0.05) at day 0. At day 40, the increases in treatments C1, C2, and ACK were 26.99%, 54.38%, and 37.02%, respectively (P<0.05). Compared with ACK, the soil organic matter content in treatment AC2 increased by 29.33% at day 0, with no significant difference at day 40. Adding chlorella as an exogenous substance to the soil significantly increased soil organic matter levels, with the effect intensifying as the addition amount increased. Compared with treatments only adding chlorella, the addition of actinomycetes agents reduced the utilization rate of exogenous organic matter in the early stage (0～20 days) and extended the utilization time. 3) Compared with CK, the soil total nitrogen content in treatments C1 and C2, which only added chlorella, increased by 15.30% and 47.56%, respectively, at day 0. At day 40, the increases reached 41.50% and 91.25%, respectively. Compared with ACK, which only applied actinomycetes, treatments AC1 and AC2, which simultaneously added chlorella and actinomycetes, showed increases in soil total nitrogen content of 15.02% and 33.06%, respectively, at day 0. At day 40, the increases were 34.03% and 58.43%, respectively. The addition of chlorella and actinomycetes increased soil total nitrogen content, with the increase positively correlated with the amount of chlorella added. The combined application of algae and bacteria slowed the consumption rate of total nitrogen. The soil C/N ratio in all treatments was more stable compared with CK, with no significant changes over time. 4)At day 40, compared with CK, all treatments accelerated soil nitrogen mineralization, with the proportion of inorganic nitrogen to total nitrogen significantly increasing in the order of C1 (29%) < AC1 (31%) < AC2 (50%) = C2 (50%). 5)Adding chlorella significantly slowed the one-dimensional vertical infiltration process of soil water. When the wetting front depth reached 30 cm (i.e., after the infiltration process was completed), the times taken for treatments CK, C1, C2, ACK, AC1, and AC2 were 19, 29, 38, 23, 29, and 37 minutes, respectively. Compared with CK, the increases in infiltration time for the treatments were: 100% (C2) > 94.7% (AC2) > 52.6% (C1) = 52.6% (AC1) > 21.1% (ACK). The actinomycetes agent had no significant effect. In conclusion, the application of Chlorella and Actinomycetes have an improvement effect on the nitrogen conversion and water infiltration characteristics of aeolian sandy soil, and provide theoretical support for the research and development of algal bioamendments.