Pollution of heavy metals poses a huge threat to food security and human health， and many methods for repairing the pollution of heavy metals in farmland have been developed. The supplementation of selenium significantly reduces the absorption of heavy metals by crops， while promoting their growth in soils polluted by heavy metals. The application of selenium has become a new way to mitigate the absorption of heavy metals by crops. This article reviewed five mechanisms including the alteration of the bioavailability of heavy metals in soil， competition between selenium and heavy metals in plant uptake channels， the promotion of forming iron plaque in plant roots， the induction of morphological and structural changes in plant roots， the regulation of gene expression involved in the chelation and transport of heavy metals in plants by which selenium mitigates the absorption of heavy metals by crops. The potential risks and priorities of studying selenium in mitigating the absorption of heavy metals by crops in the future were prospected. It will provide insights and a scientific basis for the use of selenium as a highly efficient inhibitor of the absorption of heavy metals in agricultural practices.