[Objective] The effects of three types of microalgal fertilizers and their varying application rates on soil salinity, physiological indicators, and maize yield were explored, in order to provide a new scientific basis for the enhancement of saline soil. [Methods] A field experiment was conducted using saline alkali collected from the Tumochuan Plain. Three kinds of microalgal fertilizer (designated as W₁, W₂, and W₃) were formulated for the experiment. Each microalgal fertilizer was established with three levels of application (15, 30, and 45 L/hm², designated as N₁, N₂, and N₃, respectively), a control without fertilizer, resulting in a total of 10 treatments. [Results] ① Regarding the physical and chemical parameters of soil, the application of microalgal fertilizer considerably decreased soil bulk density by 4.11% to 12.34% compared to the control treatment. Soil porosity increased from 10.82% to 38.31%. The soil pH value and salt concentration fell by 1.82%—9.9% and 17.12%—47.66%, respectively. ② As for maize growth, compared with the control treatment, the plant height, stem diameter, and leaf area index of maize subjected to the microalgal fertilizer treatment increased from 1.12% to 18.47%, 1.15% to 29.02%, and 22.5% to 74.14%, respectively. The 100-grain weight and yield improved by 16.02%—48.31% and 15.73%—41.31%, respectively. Maize yield had a significantly negative correlation with soil bulk density and pH value while demonstrating a significantly positive correlation with the leaf area index. [Conclusion] The effect of the W₂ microalgal fertilizer applied at a rate of 30 L/hm² (W₂ N₂ treatment) on improving saline soil and increasing maize yield was better; it should therefore be given priority when selecting microalgae to improve saline soil in the Tumochuan Plain.