Abstract: Frequent extreme weather events have exacerbated shallow soil erosion, which seriously threatens the stability and safety of engineering structures in coastal and reef areas. A sand stabilization technology is proposed using filamentous fungi and wheat bran. The growth conditions of fungal mycelium are optimized through single-factor experiments and response surface methodology, while the water stability and environmental impact of the reinforced soil are evaluated using disintegration and leachate toxicity tests. Experimental results reveal that temperature has a significant influence on fungal growth during the early curing stage, while nutrient solution concentration plays a more prominent role during the later stages. In contrast, moisture content exerts a consistent and significant effect throughout the entire curing process. Based on the desirability function method, the optimal curing conditions for fungal-reinforced soil are determined to be a temperature of 25℃, a moisture content of 10%, and a nutrient solution concentration of 10 mg/L. Compared to untreated samples, the incorporation of fungal mycelium results in maximum increases of 78.8% in peak strength and 369.2% in elastic modulus. The reinforced sand also exhibits significantly improved water stability, with a disintegration ratio of zero after 14 days of immersion and minimal environmental impact from the leachate. The experimental results confirm that the sand reinforcement technique based on filamentous fungal growth holds practical potential for applications in shallow soil stabilization and coastal slope protection.