In order to reveal the effect of arc glow plasma NiCr co-infiltration treatment on the surface composition, structure and seawater aerobic corrosion resistance of Q235 carbon steel. Ni-Cr alloying layer was prepared on Q235 carbon steel by arc glow plasma plating. The phase composition, surface morphology and cross-sectional element distribution of Ni-Cr alloying layer were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). The corrosion electrochemical behavior of Ni-Cr alloy layer in seawater aerobic bacteria was tested and analyzed by electrochemical test technology. After arc glow plasma Ni-Cr carburizing, a layer with a thickness of about 50 μm was formed on the surface of Q235 carbon steel, and the phase of the alloying layer was Ni2.9Cr0.7Fe0.36 solid solution. When Q235 carbon steel was immersed in aerobic bacteria, a biological corrosion film was formed on the surface. The existence of the corrosion film makes the corrosion potential of Q235 carbon steel move negatively and the local corrosion resistance was reduced. Compared with Q235 carbon steel, the surface energy of Ni-Cr alloying layer was reduced and the surface contact angle reaches 111°. After the Ni-Cr alloy layer was soaked in aerobic bacteria for 11 days, bacterial adhesion was observed only in a few local positions, and no obvious corrosion film was observed. Q235 carbon steel was seriously corroded when immersed in aerobic bacteria. After soaking for 5 days, a corrosion product film formed by corrosion products, culture medium and bacteria was formed on its surface. The corrosion products can promote the formation of biofilm. The Ni-Cr alloying layer reduces the surface energy of Q235 carbon steel surface and hinders the formation of biofilm bottom film. At the same time, the formed passivation layer had a certain barrier to the medium and significantly improves the corrosion resistance of aerobic bacteria.