Graphene oxide (GO) was prepared by Hummers method, then a series of composites consisting of lanthanum doped titanium dioxide and graphene oxide （GO-La3 /TiO2）were in situ synthesized via citric acid chelating sol-gel step, and subsequently lanthanum doped titanium dioxide and graphene (rGO-La3 /TiO2) composite photocatalysts were obtained by sodium borohydride reduction method. The composite materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy technology. The influences of GO addition amount on the composites photocatalytic activity and the effects of composite photocatalysts mass on the methyl orange degradation rate were investigated, respectively. The results showed that the dispersion of lanthanum doped nanometer titanium dioxide on the graphene surface was improved effectively; the photocatalytic activity of rGO-La3 /TiO2 was obviously higher than that of La3 /TiO2, and the photocatalytic performance of rGO-La3 /TiO2 was effected greatly by the addition amount of GO; the optimum mass of composite photocatalysts was 0.10g to degradation of methyl orange.