Abstract: The edge of the desert of Northwest China faces problems such as drought, water shortage, soil desertification, serious water leakage and fertilizer leakage, which seriously affect the normal growth of plants and restrict the sustainable development of agriculture and forest and fruit industry. In this study, indoor experiments were carried out to explore the effects of natural sodium bentonite mushroom residue composites on soil water and fertilizer retention performance. Teabag and soil column simulation method were used. Pure bentonite (P) and three treatments of composite materials were designed including bentonite-mushroom residue-humic acid composite (JF), bentonite-mushroom residue-amino acid composite (JA) and bentonite-mushroom residue-cow dung composite (JN). Each treatment of composite materials included four levels of bentonite-mushroom residue ratio of 1:2, 1:2.5, 1:3 and 1:3.5. For the treatment of P, four proportions of bentonite was designed including 3%, 5%, 7% and 9%. For the JF, the humic acid accounted for 1.5%. For the JA, the amino acid accounted for 1.5%. For the JN, the dried cow dung accounted for 1.5%. The effects of water leakage and fertilizer leakage in sandy soil of each treatment were analyzed. The results showed that the treatments of group JF, JA, and JN improved the water absorption ratio and water holding capacity of sandy soil than that of the treatments of group P to a greater extent. Under the condition of soil column leaching, with the increase of the amount of bentonite (P), the cumulative leakage of water and nutrients showed a decreasing trend. When the amount of pure bentonite accounted for 3% to 9% of the total sandy soil, the cumulative leakage of water decreased by 18.00% to 26.17%. Among the cumulative leakage of nutrients, the cumulative leakage of nitrogen decreased by 11.58% to 27.22%. In addition, the cumulative leakage of potassium decreased by 2.82% to 7.78%, and the cumulative leakage of phosphorus decreased little. In the composites of JF, JA and JN, when the ratio of bentonite to mushroom residue was 1: 2, the cumulative leakage of water and nutrients decreased greatly. Among them, the water cumulative leakage decreased by 25.53% to 30.31%. The cumulative leakage of nitrogen was decreased by 25.66% to 32.36%. Besides, the potassium cumulative leakage decreased by 6.35% to 10.73%, and the phosphorus cumulative leakage rate decreased slightly. According to the results of this study, the decrease of JF1 treatment was the largest, indicating that the water and fertilizer retention effect is the best when the amount of bentonite is half of the amount of mushroom residue and the auxiliary material is humic acid. It also indicated that the addition of mushroom residue and humic acid could obviously promote the performance of sandy soil in water and fertilizer retention. The experimental results showed that the addition of natural sodium bentonite mushroom residue composite to sandy soil could improve the performance of water and fertilizer retention of sandy soil, especially in reducing the loss of nitrogen leaching. The results of this study can provide valuable information for the rational utilization of plant fibrous agricultural wastes, such as natural sodium bentonite and mushroom residue to improve the utilization rate of water and fertilizer in the agricultural and forestry planting areas of Northwest China.