Objective To study the effects of different kinds of carbon nanotubes on the properties of chitosan composite films. Methods Different mass fractions of common multi-wall carbon nanotubes (MWNT) and carbonyl multi-wall carbon nanotubes (MWNT-COOH) were respectively incorporated into chitosan films using solution blending. The composite films prepared were then characterized by swelling test, moisture permeability measurement, tensile testing, SEM, and antimicrobial experiment. Results With low loadings of MWNT and MWNT-COOH (1%), the moisture barrier properties and the tensile strength of both composite films were considerately improved compared to those of the neat chitosan film, especially the MWNT-COOH-blended film. The composite films also displayed improved antibacterial properties towards E. coli compared to the neat chitosan film. Conclusion At the same loading, the composite films containing MWNT-COOH showed better performance compared to the films containing MWNT, which might be attributed to the stronger binding force between MWNT-COOH and chitosan.