Abstract: In agriculture production, plant health is threatened by pathogens parasitic on seeds; hence, it is necessary to disinfect harvested seeds before germination. In this study, a technique of gliding arc plasma treatment was proposed and investigated. The experiment was conducted to treat Astragalus membranaceus (A. membranaceus) seeds that were artificially infected with Fusarium oxysporum (F. oxysporum). The plasma treatment duration varied from 30 s to 270 s. Direct and indirect treatments were compared to evaluate the inactivation efficiency of the F. oxysporum spores on the surface of seeds. The results indicated that the direct treatment behaved significantly better in disinfection than the indirect way. Meanwhile, experiments of the quantitative assessment of seed germination were also conducted, including the germination rate, the germination potential, and the germination index. The results showed that the inactivation efficiency increased as the plasma treatment time was extended. When the treatment time was 90 s, the inactivation efficiency reached more than 98%. The plasma treatment of 270 s had a complete devitalization of F. oxysporum spores on the surface of the seeds. After the treatment of 30 s and 90 s, the seed germination parameters improved significantly. This study verified the inactivation efficacy of gliding arc discharge plasma under atmospheric pressure. The technique of gliding arc treatment shows advantages of energy saving and adaptation and has the potential to be utilized in industry.