Abstract: Five types of rare earth electrodes were produced by adding different amounts of cerium iron alloy to the original formula of the A147 electrode coating. Spectral information of the arc during welding was collected using a spectrometer; high-speed cameras were used to capture arc morphology and droplet transition information; and the NI PXI data acquisition system was used to collect electrical signal information.Studied the effect of rare earth cerium on arc and droplet transition behavior. The results showed that in the arc plasma, the characteristic spectral lines of Fe, Mn, and Cr atoms were predominant. The addition of cerium to the flux could ionize in the arc and participate in the arc conduction process. Moreover, the thermal ionization process of cerium atoms led to arc contraction, while the addition of cerium iron alloy increased the melting point of the welding rod coating, making it easier for the welding rod to form a welding sleeve, which exacerbated the arc contraction effect, significantly increased the weld penetration, and was beneficial for achieving thick plate welding with the welding rod arc. Moreover, by adding cerium iron alloy to promote the formation of slag wall transition and droplet transition, the probability of droplet deviation was significantly reduced, the welding spatter rate was lowered, the arc height adjustment range was increased under the condition of ensuring good formation, and the technical requirements for welding were reduced.