To examine the ability of potassium humate (0, 1000, 2000 and 3000 ppm) for lessening the deleterious impacts of saline water (0, 1.4, 2.8 and 4.2 dS/m) on Rosmarinus officinalis plant, a pot study was undertaken at the Nursery of Ornamental Plants, Fac. Agric., Minia Univ. during the two experimental seasons 2022 and 2023. Data showed that all examined traits of vegetation development (plant height, branches number/plant, and herb fresh and dry weights) were decreased by increasing salinity levels (2.8 and 4.2 dS/m) compared with control in both cuts during both seasons. Opposite trend was obtained with the low concentration (1.4 dS/m). It was found that, while the essential oil (%) and its yield/plant were increased under (1.4 and 2.8 dS/m), the essential oil (%) and yield were significantly decreased under (4.2 dS/m) in both cuts during both seasons.  The pigments content and NPK (%) took the same trend of the vegetative growth. While both Na (%) and proline content (µg/g) in dry leaves were increased by increasing salinity levels during the second cut in both seasons. All of the aforementioned characteristics of vegetation development, essential oil output and some chemical compositions were significantly improved by potassium humate treatments, with the exception of Na% and proline content (µg/g) over both seasons. In this concern, 3000 ppm potassium humate was the most effective treatment. There was a notable interaction impact between the two parameters under investigation for all examined parameters, with the best interaction treatment recorded with 1.4 dS/m in combination with potassium humate (3000 ppm). In conclusion, the negative effects of salinity stress may be mitigated by spraying plants with 3000 ppm of potassium humate.