Abstract: Rare earth elements are effective strong purifiers and modifier used in the steel industry, and have great potential in the manufacture of composite plates. The addition method, addition amount, and strengthening mechanism of rare earth elements in related products are worthy of exploration. The different mass fractions of CeO₂ powder were mixed into the duplex stainless steel powder, and the 2205 duplex stainless steel cladding layer was manufactured on the low-carbon steel plate Q345 by the plasma arc cladding method. The influence of CeO₂ content on the macroscopic morphology,microstructure, and properties of the cladding layer was investigated. The results show that adding an appropriate amount of CeO₂ can reduce the dilution rate of the cladding layer, refine the cladding microstructure by heterogeneous nucleation and other mechanisms, improve the mechanical properties of the cladding layer by modifying impurities and fine-grain strengthening, purify the steel melt by strengthening impurities, and improve the corrosion resistance of the cladding layer.There is an optimal value of CeO₂ addition, and the mechanical properties and corrosion resistance of the cladding layer are best when the mass fraction is 1.0 wt%.