采用固体高分辨核磁共振、顺磁共振和Ｘ射线光电子能谱等方法研究了改性的Ｙ型分子筛（ＳＲＹ和ＳＲＮＹ）的钒中毒机理和添加稀土的抗钒作用。结果表明，沉积在分子筛表面的钒物种，在氧化气氛下分解，形成含氧钒离子；在催化剂再生的高温水热过程中，进一步反应生成具有强酸特性的钒酸，从而加速了分子筛骨架结构的破坏，导致了裂化反应活性的下降。稀土化合物作为钒物种的捕获剂与生成的钒酸形成稳定的钒酸盐，一方面减缓了钒的迁移速率，另一方面抑制了对分子筛骨架的破坏。在采用的多种稀土氧化物添加剂中，Ｃｅ２Ｏ３具有较高的保护ＳＲＹ分子筛结构的能力 The mechanisms of vanadium poisoning and the anti-vanadium addition of rare earths were investigated by means of high-resolution nuclear magnetic resonance, paramagnetic resonance and X-ray photoelectron spectroscopy. The results show that the vanadium species deposited on the surface of molecular sieve decomposes in an oxidizing atmosphere to form vanadate ions. During the high-temperature hydrothermal process of catalyst regeneration, vanadium acid with strong acid character is further reacted to accelerate the formation of Damage, leading to a decline in the cracking reaction activity. Rare earth compounds, as capture agents of vanadium species and vanadic acid generated to form stable vanadate, slow down the migration rate of vanadium on one hand and inhibit the destruction of molecular sieve framework on the other hand. Of the various rare earth oxide additives employed, Ce2O3 has a high ability to protect SRY molecular sieve structures