Abstract: This article presented a review of the types and sources of organic acids in soil and their effects on the chemical behavior and bioavailability of heavy metals in soil. On the one hand, the factors affecting the differentiation of organic acid secretion and the mechanism of changing soil pH were summarized; on the other hand, it focused on the influence mechanism of rhizosphere organic acids on the occurrence and bioavailability of heavy metals in the soil. Rhizospheres organic acids can not only activate nutrients and detoxify metals through abiotic effects such as acidification, complexation and exchange, but also change the form or valence of heavy metals in the soil through biological effects such as being an electron donor and acting as an electron transfer body, thereby affecting the migration and transformation of heavy metals in the soil. By clarifying the basic properties of organic acids and their influence mechanisms on the chemical behavior and bioavailability of heavy metals in the soil, it was expected to provide a theoretical basis for the wider scientific use of organic acids and the treatment of soil heavy metal pollution.

Key words: organic acid, rhizosphere, heavy metal, form, bioavailability