In this article, packaging bags composited with selective barrier film and moisture absorbent nonwoven fabrics were prepared to design a kind of functional bags, which can inhibit the growth of aflatoxin of peanuts. The influences of the super-absorbent fiber (SAF) and jute fiber on the internal relative humidity (RH) were investigated. It is found that jute nonwoven/selective barrier film composite bag can prevent the growth of aflatoxin B1 of peanuts under the environment studied in this article because peanuts with higher moisture content can reduce O2 content inside the bag by the aerobic respiration, achieving the modified atmosphere packaging (MAP) effect. In addition, a low RH micro-environment can be achieved by using SAF as moisture absorbent. It is promising to design a packaging bag with the effect of inhibition of the growth of aflatoxin of peanuts, by selecting proper moisture absorbent and selective barrier film of the composite bag. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40190.