Abstract: Objective Fungal pollution on the surface of rice noodles affects the quality and safety of rice noodles, but few studies focused on decontaminating rice noodles from fungal contamination. In this study, cold plasma technology to use to decontaminating rice noodles from fungal contamination with Penicillium oxalicum, and its antifungal effect and mechanism were investigated, which can provide reference for rice noodle preservation. Methods Based on cold plasma treatment technology, the antifungal effect and mechanism of cold plasma treatment were studied in terms of inactivation efficacy, spore germination and mycelium development, cell membrane integrity, and leakage of intracellular components. Results The efficacy of cold plasma against P. oxalicum gradually increased with the increase of treatment time, and 100% of kill rate could be achieved after treatment for 60 s. Cold plasma treatment could effectively inhibit spore germination and mycelia development. After 60 s of treatment, the spore germination rate decreased by 57.79% compared with the control group. Mycelia development was inhibited in the treatment group, and no germination of spores was observed completely after 240 s of treatment. Cold plasma can change the integrity and permeability of fungal plasma membrane. With the extension of treatment time, the PI staining rate of cells was increased. When the treatment time was 180 s, the staining rate was increased by 94% compared with the control, and the extracellular electrical conductivity was increased with the extension of treatment time representing an increase of 73% compared with the control. The studies showed that cold plasma had no significant effect on reducing sugar precipitation of rice noodles, and can reduce the dissolution index of rice noodles, which was conducive to the retention of nutrients and quality of rice noodles. Conclusion In this study, the cold plasma could was shown to exhibit high efficacy in decontaminating rice noodles from fungal contamination with P. oxalicum, and did not adversely affect quality parameters of rice noodles, which could provide references for preservation of rice noodles and rice-based food.