To improve oxidation resistance, prevent Cr evaporation and maintain appropriate electrical conductivity of AISI 430 stainless steel (430 SS) as the solid oxide fuel cells' (SOFCs) interconnect, a double-layered Co-Mn-O spinel coating is fabricated successfully on 430 SS via a simple double glow plasma alloying process (DGPA) followed by heating in the air (preoxidation treatment). The double-layered Co-Mn-O spinel coating is composed of a thick MnCo2O4 spinel outlayer and a thin mutual-diffused (MnCoFe)(3)O-4 oxide innerlayer. The isothermal and cyclic oxidation measurements are used to investigate the oxidation resistance, and the ASR test is performed to evaluate the conductivity for the coated and uncoated specimens. The coated specimen has a lower oxidation kinetics rate constant (9.0929 x 10(-4) mg(2) cm(-4) h(-1)) than the uncoated one (1.900 x 10(-3) mg(2) cm(-4) h(-1)) and the weight gain of the coated specimen (0.84 mg cm(-2)) is less than that of bare steel (1.29 mg cm(-2)) after 750 h oxidation. Meanwhile, the coated specimen holds a lower area specific resistance (0.029 Omega cm(2)) compared to the uncoated one (2.28 Omega cm(2)) after 408 h oxidation. Furthermore, the compact Co-Mn-O spinel coating can effectively impede Cr-volatilization. Additionally, the probable mechanism of the Co-Mn alloy conversion into spinel and the electronic conduction behavior in the spinel are discussed. The effects of mutual-diffused oxide innerlayer on oxidation behavior and conductivity are investigated. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.