In this work, a novel isotactic polypropylene (PP)/fibrous cellulose (FC) composite containing a poly(ethylene oxide) (PEO)/TiO2 was prepared, and its oxo-biodegradation behavior was studied. FC loading of 5 and 1% resulted in an opaque film and relatively good transparence, respectively. Fourier transform infrared (FTIR) spectra of the nonphotodegraded composite samples revealed little PP auto-oxidation under the melt-mixing condition. Ultraviolet irradiation enhanced the auto-oxidation of the composite. FTIR analyses of the composite indicated that TiO2 and PEO functioned as the initiator and accelerator of PP auto-oxidation, respectively. In addition, even with 1% PEO, the accelerator effect was enhanced by the spreading of the degraded PEO component from other areas when the film thickness was increased. All PP/PEO/TiO2/FC composites with a PEO content varying from 0.3 to 5% showed a Young's modulus value of similar to 180% higher than that of pristine PP. Biodegradability of the photodegraded composite was confirmed by a soil burial test. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013