Abstract: The national scheme has been released as more than 50% of treatable desertified land by 2020 and all treatable desertified land by 2050. This study aims to explore the impact of the combined use of Chlorella and Actinomycetes on the nutrient transformation and water infiltration in aeolian sandy soil. The aeolian sandy soil was then selected in Hotan Prefecture. Six treatments were constructed to add the different amounts and ratios of Chlorella and Actinomycetes (algae-bacteria agent) into 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 also incubated in the dark for 40 days. At the same time, a series of measurements were monitored on the soil pH, organic matter, total nitrogen, NH4+-N, and NO3--N indicators. One-dimensional vertical infiltration tests were carried out to determine the soil infiltration after incubation. The results indicated: 1) The pH values of the soils in the 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), compared with the CK. The combined application of algae and bacteria also triggered the great variation in the pH values. 2) The content of soil organic matter in the treatment C2 increased by 37.69% (P<0.05) on the initial day, compared with the CK. There was an increase in the treatments C1, C2, and ACK by 26.99%, 54.38%, and 37.02%, respectively (P<0.05) at day 40. Compared with the ACK, the content of soil organic matter in the treatment AC2 increased by 29.33% on the initial day, with no significant difference at day 40. The chlorella was added as an exogenous substance, in order to significantly increase the soil organic matter levels, with the intensifying effect as the addition amount increased. Compared with the treatments only adding chlorella, the actinomycetes agents were added to reduce the utilization rate of exogenous organic matter in the early stage (0~20 days), and then to extend the utilization time. 3) Compared with the CK, the soil total nitrogen content in the treatments C1 and C2, which only added chlorella, increased by 15.30% and 47.56%, respectively, at day 0. The increase reached 41.50% and 91.25%, respectively, on day 40. Compared with the ACK, which only applied actinomycetes, the treatments AC1 and AC2, which simultaneously added chlorella and actinomycetes, showed an increase in the soil total nitrogen content of 15.02% and 33.06%, respectively, at day 0. There was an increase of 34.03% and 58.43%, respectively, on day 40. The chlorella and actinomycetes were added to increase the content of soil total nitrogen, with the increase positively correlated with the amount of chlorella added. The combined application of algae and bacteria also slowed the consumption rate of total nitrogen. There was a more stable soil C/N ratio in all treatments, compared with the CK, with no significant changes over time. 4) All treatments accelerated the soil nitrogen mineralization at day 40, compared with the CK. Specifically, the proportion of inorganic nitrogen to total nitrogen significantly increased in the ascending order of C1 (29%) < AC1 (31%) < AC2 (50%) = C2 (50%). 5) The chlorella was added to significantly slow the one-dimensional vertical infiltration of soil water. Once the wetting front depth reached 30 cm (i.e., after the infiltration was completed), the duration taken for the treatments CK, C1, C2, ACK, AC1, and AC2 were 19, 29, 38, 23, 29, and 37 min, respectively. Compared with the CK, there was an increase in the infiltration time for the treatments: 100% (C2) > 94.7% (AC2) > 52.6% (C1) = 52.6% (AC1) > 21.1% (ACK). There was no significant effect of the actinomycetes agent. In conclusion, the Chlorella and Actinomycetes were applied to improve the nitrogen conversion and water infiltration in the aeolian sandy soil. The finding can provide theoretical support to the algal bioamendments.