AbstractFoam buffer package materials composed of plant fibers have been a focus of research in recent years because of their environmentally beneficial ability to become fully disintegrated. In this study, bleached bagasse pulp was micronized using a PFI mill, and foam buffer materials were prepared using the micronized fiber. The effects of the beating degree of micronized fibers on the dimensional stability, moisture absorption, static compression, and dynamic compression characteristics were discussed. Results showed that, in both the static and the dynamic compression experiments, the buffer properties improved with an increasing beating degree. The buffer materials made of highly micronized fiber were stronger under pressure and impact. Specifically, the highly micronized fiber’s ability to absorb energy curing impact was improved, demonstrating that it can support a higher compression and impacting load in a certain deformation scope. However, during the drying process, the dimensional stability of the samples also declined with an increasing beating degree. The moisture absorption of the samples improved when the beating degree was increased.