Abstract: To study the effect of rare earth chloride on vapor phase carbonylation of methanol to acetic acid, a series of catalysts (Ni-La/AC) were prepared by loading LaCl3 onto Ni-based catalysts. The catalysts were characterized by means of BET, XRD and TPR, then were applied to the methanol carbonylation reaction after being heat treatment in nitrogen at 400 ℃ and reduction by hydrogen at 550 ℃. It was revealed that under pressurized conditions in the presence of methyl iodide, these catalysts had positire effects on induction period, conversion of methanol and yield of carbonyl products. The results indicated that Ni（5%）- La (3.8%)/AC had better catalytic activity. Compared with Ni（5%）/AC at the same operation conditions, the conversion of methanol is increased by 11.52% and the total yield of carbonyl products is improved by 12.16%.