Cadmium (Cd) contaminants with high toxicity and mobility seriously threatens the ecological environment and human safety. Hydrangea macrophylla is a potential plant for Cd-contaminated soil remediation. Exogenous organic acids have been proven to effectively enhance the phytoremediation of soil contaminated with Cd. However, research on the effects of organic acids on Cd tolerance and accumulation of H. macrophylla remains scarce. In this study, a potted experiment was performed with H. macrophylla as the research object. The effects of acetic acid (AA), citric acid (CA), and malic acid (MA) with different concentrations (2.5, 5, and 10 mmol·kg