The broad-spectrum UV filter oxybenzone is toxic to plants at environmentally relevant concentrations. Post-translational modifications (PTMs) of proteins play a crucial role in regulating plant responses to stresses. Understanding global proteomic changes that occur in response to a specific stress or can allow for specific hypotheses to be generated regarding xenobiotic tolerance. Lysine acetylation (LysAc) is one of the essential PTMs in plant signalling responses. The goal of this study was to uncover the LysAc regulatory mechanism in response to toxic exposures to oxybenzone as a first step in elucidating xenobiotic acclimatory reactions. This study reported the changes in intracellular protein expression and LysAc modification of higher plants under oxybenzone stress using the model, Brassica rapa L. ssp. chinensis. A total of 4898 proteins were identified, and 6124 sites on 2497 proteins were acetylated, 63 proteins were differentially expressed, and 162 proteins were differentially acetylated under oxybenzone treatment. Bioinformatics analysis showed that the differentially expressed and acetylated proteins were mainly distributed in the chloroplast, cytoplasm, and nucleus, which participate in many important processes such as scavenging of reactive oxygen species (ROS), stress resistance, energy generation and transport, photosynthetic carbon fixation, glycolysis, and the tricarboxylic acid cycle.