Cadmium is one of the most toxic pollutants, and excessive cadmium can inhibit plant growth and photosynthesis, interfere with mineral metabolism, and induce oxidative stress. Meanwhile, silicon is beneficial to plants and, after being actively or passively absorbed by plant roots and transported to other plant parts, mainly in the form of Si(OH)₄, can alleviate cadmium toxicity. The mechanism underlying silicon-induced cadmium detoxicification in plants varies among species, cultivars, and ecotypes, showing a silicon/cadmium concentration-dependent manner. In general, the silicon-induced reversal of cadmium toxicity can be divided into two main mechanisms:avoidance and tolerance. The avoidance mechanism mainly functions (1) at the organ level, by reducing the absorption of cadmium by plant roots and/or its translocation from roots to shoots, and (2) at the cellular level, by enhancing the cadmium adsorption capacity of the cell wall and, therefore, reducing the influx of cadmium into the symplast. The tolerance mechanism also involves a variety processes, including (1) the induction of low molecular compounds that chelate cadmium ions, thereby reducing free cadmium concentrations; (2) the reduction of oxidative stress by enhancing antioxidant mechanisms; and (3) the improvement of photosynthesis and mineral nutrition, thus promoting plant growth. Here, we review recent advances in the mechanisms underlying cadmium toxicity, the uptake and transport of silicon, and silicon-induced cadmium detoxification in plants. Based on the weakness of previous studies, the need for further research is also discussed.