The work aims to prepare oxidized microcrystalline cellulose (OMCC) cross-linked chitosan composite films and explore the effects of cross-linking on the properties of chitosan composite films. Microcrystalline cellulose (MCC) was oxidized with sodium periodate to prepare OMCC. Then, composite films with different concentrations of OMCC (0%, 1%, 3%, 5%, 7% and 9%) were successfully fabricated through solution casting method. By characterizing the composition, morphology, mechanical properties, optical properties, thermal stability and barrier properties of the composite films, the effect of different OMCC concentrations on the properties of composite films was investigated. The aldehyde groups on the surface of OMCC were cross-linked with the amino groups of chitosan. The addition of OMCC increased the tensile strength and elongation at break of chitosan films, which reached up to 43.07 MPa and 19.42% respectively. With the increase of the OMCC, the UV-blocking properties and water vapor permeability of the films were improved, while the thermal stability was almost unaffected. The OMCC cross-linked chitosan can enhance the mechanical properties and UV-blocking properties of chitosan film, which is beneficial to broadening its application in packaging field.