Abstract: Heavy metal (metalloid) pollution in soils has caused excessive accumulation of them in crops, which has become one of the serious concerns of residents in the vicinity of some polluted regions in China. Plants have developed many mechanisms, by which, to restrict the uptake, translocation and enrichment of heavy metals (metalloids) in plants. The above mechanisms are mainly related to the physical, chemical and biological processes occurring in the plant root-soil system. This review attempts to summary the mechanisms equipped by plant root system on affecting the uptake, translocation and toxicity of heavy metals (metalloids) in plants. The main mechanisms include: 1) plant roots will secrete some exudates which can bind with heavy metals so as to stabilize heavy metals; 2) plants will alter their root morphology, such as enhancing coarse root ratio, and reducing fine root numbers and root surface, in response to the exposure of heavy metals (metalloids) to reduce their uptake by plants; 3) root iron plaques (amphoteric colloid, mainly containing iron and manganese oxides) will be formed on the root surface of aquatic plants, which can adsorb cations and anions so that sequestrate heavy metals (metalloids); 4) the competition adsorption between ions with similar physicochemical properties will occur on the surface of plant roots for the same adsorbing sited on the root surface, wich can reduce the entrance probability of heavy metals into the inner cells; 5) plant cell wall contain some function groups, acting as a barrier and/or an adsorption layer in restraining the transfer of heavy metals (metalloids); 6) Casparian band in plant root endodermis can act as a barrier to block the transport of heavy metals (metalloids) between the cortex and vascular column, thus preventing their transport to the ground part; 7) metal ions with similar properties will compete with ion channels in root cell membranes, and this process affects their absorption by plants; 8) heavy metals (metalloids) that float in cells can be sequestered into root vacuoles, thereby reducing their toxicity and transport to above-ground parts of plants; 9) the overexpression of some genes in root cell membrane restricts the transport of heavy metals from root to aboveground parts. In summary, the uptake or translocation of heavy metals (metalloids) can be restrained via some mechanisms equipped by plants including: the decreased contact probability of plant roots with heavy metals (metalloids), the enhanced adsorption of heavy metals (metalloids), the uptake competition between ions, and the sequestration of heavy metals (metalloids). However, it is not clear that why the cell wall compontents of plant roots will restrain large amounts of metalloids (often occurring as anions), which needs further investigations in future.