In order to investigate the interaction of graphene oxide (GO) with different cellulose polymorphs (I and II), we synthesized cellulose (I and II)/GO composites using the sonication method. Interestingly, no new peaks were observed in the FT-IR pattern of the cellulose (I and II)/GO composites, indicating that no chemical reactions took place between GO and cellulose. The X-ray diffraction patterns of cellulose I and II/GO composites were slightly different than those observed for cellulose I and II, indicating that some physical interactions occurred between the GO and cellulose. Unexpectedly the d-spacing values and the diffraction plane at the high-angle side were most likely expanded in cellulose I rather than in cellulose II by adding GO, confirming the highest reactivity of GO toward cellulose I rather than cellulose II. Furthermore, SEM images showed that the conformal coating of GO on cellulose I was larger than that on cellulose II due to the strong adhesion between the GO and cellulose I. Cellulose/GO showed antimicrobial properties, and GO was found to be promising for textile antimicrobial finishing.