This investigation was under taken at the farm of floriculture plants, Fac. Agric., Minia Univ. throughout the two growing 
seasons of 2022 and 2023 to teste the influence of humic acid at 0.0, 1000, 2000 and 4000 ppm on Rosmarinus officinalis growth characters, essential oil production and some chemical compositions, planted under irrigation salinity (0.0, 800, 1600 and 2400 ppm NaCl). Data showed that all examined traits of vegetative development (plant height, branches and leaves number, stem diameter, leaf area, herb fresh and dry weights), essential oil productivity (% and yield ml/plant) and some chemical compositions (pigments content and NPK%) were decreased by increasing salinity level comparing with control during both seasons. At the same time, salinity concentrations increased both of Na% and proline content (µg/g) in dry leaves during both seasons. Humic acid treatments significantly increased all abovementioned traits of vegetative development and volatile oil content as well as some chemical compositions except Na% and proline content (µg/g) in dry leaves during both seasons, were decreased. The best treatment was 4000 ppm humic acid in this concern. In conclusion, treating plants with 4000 ppm humic acid can alleviate the bad effects of moderate salinity levels.