Rare earth elements have been extensively used as micro-fertilizers for crops in China. To understand the potential benefits or damages of Ce⁴⁺ on rice, the effects of Ce⁴⁺ on viability and membrane integrity of rice were investigated under hydroponic cultures. It has been found that the cell viability, electrical conductivity, pH changes, and concentration of malonyl dialdehyde did not change obviously when the content of Ce⁴⁺ was 0.5 mg/L, but varied markedly when the contents of Ce⁴⁺ were raised to 10 mg/L or more, indicating that the Ce⁴⁺ at higher concentrations severely affected the cell membrane permeability.