Lanthanum　and　nitrogen　co-doped　SrTiO3　was　prepared　by　a　mechanochemical　reaction　using　SrTiO3,　urea　and　La2O3　as　the　raw　materials.　The　samples　were　characterized　by　X-ray　diffraction,　X-ray　photoelectron　spectrometer　transmission　electron　microscopy,　and　nitrogen　adsorption-desorption　isotherm　measurements.　Lanthanum　doping　could　increase　the　doping　content　of　nitrogen　in　the　sample.　The　sample　prepared　with　0.2　mol　%　La2O3,　22　mol　%　urea　and　77.8　mol　%　SrTiO3　by　mechanochemical　reaction,　which　has　nearly　the　same　nitrogen　and　lanthanum　doping　fractions,　exhibited　high　photocatalytic　activities.　Under　the　irradiation　of　light　with　wavelength　larger　than　400,　and　290　nm,　the　photocatalytic　activity　of　nitrogen　and　lanthanum　co-doped　SrTiO3　were　2.6　and　2　times　greater　than　that　of　pure　SrTiO3.