Repairing eutrophic water bodies is a major environmental problem that needs to be solved urgently in nowadays society. Using allelochemicals released by plants to inhibit the growth of algae is an ecologically safe means of algae inhibition. Phenolic acid, as one of the main allelochemicals identified and applied at present, has been widely concerned and studied. The types of phenolic acids released by aquatic plants were summarized in this paper. The algal inhibition characteristics of phenolic acid were described from the perspectives of selective inhibition, single and combined action, structure-activity relationship, and effective algal inhibition dose. The possible algal inhibition mechanisms of phenolic acid were introduced from the perspective of physiology and biochemistry, mainly including destroying the photosynthetic system of algal cells, destroying the membrane and morphological structure of algal cells, producing reactive oxygen species, inhibiting protein synthesis of algal cells and causing programmed cell death. In the future, the degradation and migration characteristics of allelochemicals, joint and continuous action of allelochemicals, high-efficiency allelochemical development, and algal inhibition mechanism of phenolic acid can be carried out in-depth research.