Composite films were prepared by extrusion technology using zein, poly propylene carbonate (PPC) and nano-TiO2. The samples were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR) and mechanical properties experiments. Based on the Halsey equation, the relationship between tensile strength and relative humidity is established to predict the tensibility of the composite films under different humidity conditions. The SEM study revealed that zein and PPC could form a homogeneous network structure and uniform distribution of nano-TiO2 in films. Furthermore, the composite films presented a good thermal stability. The structural analysis showed that ester groups were major forces responsible for complex formation. In addition, the photocatalytic degradation of methyl orange (MO) followed pseudo first-order kinetics was also investigated, and the removal rate of MO could achieve up to 85.06%. The antibacterial experiment indicated that zein/PPC/nano-TiO2 film had good activity against the E. coli, S. aureus and salmonella. The obtained results indicated the designed film may be a potential alternative for food packaging.