A series of La-modified ZSM-5 were prepared by hydrothermal treatment and incipient wetness impregnation. Compared with those of pristine ZSM-5

an increase in lattice constants and the amount of strong

weak and the total acid cites of La-modified ZSM-5 by the hydrothermal treatment occurs. The amount of acid cites of by La-modified ZSM-5 by incipient wetness impregnation increases

however

the lattice constants does not change. High yields of ethylene and propylene were obtained on both kinds of modified samples tested in the catalytic cracking of hexane. The yields of ethylene and propylene were achieved on the samples modified by hydrothermal treatment at WHSV 6 h-1 (23.39% of ethylene

25.17% of propylene)

which are 2% and 4% larger than those of the pristine ZSM-5 samples (21.19% of ethylene

21.04% of propylene)

and slightly better than those of the samples modified by incipient wetness impregnation. In the long-term experiment of hexane cracking with at WHSV 4 h-1

the samples modified by hydrothermal treatment (2000 min) and incipient wetness impregnation (1600 min)

exhibited much longer durability than the pristine ZSM-5 sample (800 min). It suggested that the hydrothermal treatment is better modification method in the preparation of La-modified ZSM-5 catalyst to improve the performance of hexane catalytic cracking.