Catalytic conversion of n-octane and light diesel oil was carried out over ZSM-5 comodified with gold and lanthanum by modified deposition-precipitation and wet impregnation methods. A series of ZSM-5 modified with gold catalyst (Au/ZSM-5) and comodified with gold and lanthanum (Au/La-ZSM-5) were prepared and their catalytic activity were comparied to study the relationship between catalytic activity and Au-La loading. The catalytic cracking reaction over modified ZSM-5 was carried out at 260-460 degrees C under ambient pressure. The catalysts were characterized by X-ray diffraction (XRD), N-2 adsorption-desorption, temperature-programmed desorption of NH3(NH3-TPD), transmission electron microscopy (TEM) with EDS analysis. Compared with Au/ZSM-5 catalyst, the modification of lanthanum promoted the cracking and prevented the accumulation of gold, thus stabilizing gold nanoparticles and improving the catalytic performance.