This study examined how various organic carbon additives influence the growth of tomato seedlings and the physicochemical characteristics of rhizosphere soil under phenolic acid stress. Tomato pot experiments were conducted and a total of 8 treatments were set up, including conventional cultivation (CK), phenolic acid stress (T1), phenolic acid stress+ KOH (T2), and treatments involving the addition of external phenolic acid mixed with KOH and different organic carbon sources. The organic carbon sources used were potassium acetate (T3), alginic acid (T4), fulvic acid (T5), humic acid (T6), and γ-polyglutamic acid (T7). After 30 days of transplantation, tomato seedling growth indicators, physiological indicators, rhizosphere soil physicochemical properties, and soil enzyme activities were measured. Correlation analysis was performed to explore the relationship between physiological indicators of tomato seedling and soil environmental factors under different treatments. The addition of organic carbon sources effectively promoted tomato growth. Among all the treatments, the T6 treatment showed the best effect, compared with T1 treatment, the root vitality of tomato seedlings in T6 increased by 122.9%, leaf enzyme activity increased by 16.7% to 149.1%, root MDA and soil total phenolic acid content decreased by 59.0% and 44.2% respectively, soil pH, organic matter, alkali nitrogen, and available potassium content increased by 5.1%, 27.4%, 22.0%, and 119.2% respectively, and soil enzyme activity were also increased by 9.0% to 28.7%. Redundancy analysis and Spearman correlation analysis results showed a significant negative correlation between above ground and root fresh weight of tomato plants with soil total phenolic acid content, and a significant positive correlation with soil organic matter, sucrase, polyphenol oxidase, and catalase. Treatment T6 had opposite regulatory effects on these five key soil environmental factors that drove the growth indicators of tomato seedlings compared to treatment T1. Organic carbon sources can alleviate the allelopathic stress effect of phenolic acid on tomato growth by enhancing crop physiological activity, improving soil physicochemical properties, and increasing crop rhizosphere soil enzyme activity, among them, humic acid exhibited the optimal effect.