Aiming at the problem that the steamed buns are prone to mildew during storage, polyvinyl alcohol (PVA) was used as the resin matrix, and the onion matrix mother liquor was prepared by using onion juice as the main antibacterial matrix, then coated on kraft paper to make antibacterial packaging. By observing the moldy condition of the steamed buns, the antibacterial effects of the onion matrix on the steamed buns were judged. The effects of antibacterial solution on the tensile strength, water vapor transmission coefficient, and oxygen permeability of bacteriostatic paper were studied experimentally. The results showed that under the same conditions, the beginning of mildew of samples with the onion-based bacteriostatic packaging paper was later than that of the blank samples. With increase in the mass fraction of the onion substrate, the antibacterial effect showed an upward trend. After the mass fraction of the substrate reached a certain level, the antibacterial effect tended to be saturated with the increase in the mass fraction of the onion substrate. The water vapor transmission coefficient and oxygen permeability of the coated packaging paper were improved compared to those of the kraft paper, and the tensile strength was enhanced.