This study aimed to explore the potential benefits of exogenous hormones. We used salicylic acid (SA) treatments to compare the physiological responses and protein expression differences of sunflowers treated with different irrigation deficit levels. The results showed: i. SA helped waterdeficient sunflowers significantly increase the relative water content, inhibit transpiration rate (Tr), and stomatal conductance (Cleaf); therefore, SA effectively improved water efficiency (We) in the deficit range of 40%-60%. ii. Proteomic analysis revealed that 142 of 1,683 differential proteins in waterdeficient sunflowers treated with SA exhibited significant changes. Of those, 104 were upregulated and 38 were downregulated. The Cluster of Orthologous Groups of Proteins (COG) annotation revealed that SA regulated translation and transcription processes, conversion of energy, carbohydrates, and amino acids. ⅲ. Subcellular localization analysis revealed that the target proteins regulated by SA were primarily distributed in the chloroplasts, cytoplasm, and nucleus, indicating that SA has multiple effects on the physiological processes. ⅳ. The Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that SA improved translation and transcription processes and accelerated photosynthesis and energy consumption-related processes, thereby enhancing plant stress resistance. In summary, we conclude that SA enhances the tolerance of sunflowers to water deficit by regulating their own reactions, such as stomata and photosynthesis, and stimulating environmental adaptive responses such as secondary metabolism signals. The results support the improvement of agricultural irrigation water efficiency.