Salinity severely reduced crop productivity. In this work, the effectiveness of Spirulina platensis (100 mg/l) as a foliar growth stimulator was tested for its ability to reduce the harmful effect of salinity on Phaseolus vulgaris L. plants. The experiment was divided into four groups as follows: G₁ (control), G₂ (200 mM NaCl), G₃ (100 mg/l of Spirulina platensis), and G₄ (200 mM NaCl + 100 mg/l of Spirulina platensis). The results declared that shoot weight, plant height, leaves number, during the vegetative growth stage, pods number/plant, seed number/pod, pods weight during fruiting stage, as well as content of carotenoids, chlorophyll a+b, 100-seed weights, photosynthetic activity (assimilation of ¹⁴CO₂), and total protein content reduced considerablyin salt-stressed Phaseolus vulgaris. When compared to salt-stressed plants, the above metrics were enhanced by G₄. In comparison to the control, the presence of salinity increased the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), peroxidase activity (POD), malondialdehyde (MDA), free proline, transpiration rate, and total phenol. Additionally, compared to plants under salt stress, G₄ application (200 mM NaCl + 100 mg/l of Spirulina platensis) decreased the aforementioned metrics. Treatments of Phaseolus vulgaris with 200 mM NaCl + 100 mg/l of Spirulina platensis considerably increased the macronutrient content and decreased the Na⁺ and Cl⁻ levels as compared to G₂. Obtained results proved that foliar applications of S. platensis at 100 mg/l have a high potential for improving growth, photosynthetic capacity, yield production, decreased ROS-induced oxidative damage, and reducing DNA damage in salt-stressed Phaseolus vulgaris.