Later Liang was in turn conquered by its northern rival Later Tang, and Cui Xie became deputy chief imperial censor (御史中丞, Yushi Zhongcheng) in the new administration of Later Tang's first emperor Li Cunxu. However, in his reports, he would often make grammatical or diction errors, and therefore was often called out and punished for it. He was also said to be impressive in appearance and capable of speech, but having logical lapses in his arguments, such that he gained a reputation for having style without substance.[3]
Early in the subsequent administration of Li Cunxu's adoptive brother and successor Li Siyuan, Cui served successively as the minister of rites (禮部尚書, Libu Shangshu) and then as the minister of worship (太常卿, Taichang Qing).[3] In 927, after Li Siyuan had removed two chancellors left over from Li Cunxu's administration, Doulu Ge and Wei Yue, he was considering who else to commission as chancellors to replace Doulu and Wei. One of his chiefs of staff, Kong Xun, did not like having chancellors from north of the Yellow River — i.e., from the territory of Later Tang's predecessor state, Jin — and thus recommended Cui. The chancellor Ren Huan recommended Li Qi, but fellow chancellor Zheng Jue disliked Li Qi, and therefore persuaded Kong's chief of staff colleague An Chonghui — who was then the most powerful official at Li Siyuan's court and with whom Kong was closely aligned, that Li Qi was corrupt and unsuitable. And therefore recommended Cui as well when they discussed the matter before the emperor. Upon hearing An's recommendation, Ren responded:[4]
An Chonghui does not know the officials at court well, and therefore was deceived. While Cui Xie is from a prominent family, he does not know many words. I am already an unlearned chancellor. How can there be another chancellor like Cui Xie, to draw the laughter from the entire empire?
Li Siyuan himself suggested that the imperial scholar Feng Dao might be suitable, and then ordered these officials to rediscuss the matter. This drew Kong's displeasure about how Ren interfered with his recommendation, and he became even more determined to have Cui made chancellor. When An subsequently discussed the matter with Ren again, Ren compared choosing Cui over Li Qi to choosing beetle dung over fragrant styrax balls. Still, with Kong making daily compliments of Cui and attacks against Li Qi, eventually, Cui and Feng were made chancellors with the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), and Li Qi was not.[4]
It was said that Cui Xie did not handle many of the important matters of state as chancellor, and that whenever he had to author important documents, he had others write them for him. At that time, it was felt that the imperial university was being neglected, and Li Siyuan therefore had Cui take on the additional responsibility as the principal of the imperial university. He subsequently proposed that 200 students be admitted each year, a proposal that was considered by the popular opinion at the time to be inadequate.[3]
In early 929, Li Siyuan was returning from the eastern capital Daliang to the then-capital Luoyang, with the imperial officials attending him on the trek. While on the way, Cui Xie died at Xushui (須水, in modern Zhengzhou, Henan),[1] due to a stroke. He was given posthumous honors, and the posthumous name Gongjing (恭靖, "respectful and meek").[3]