In 630, when Emperor Gaozu's son Emperor Taizong of Tang sent the general Li Jing to attack Tujue's Jiali Khan Ashina Duobi, Ashina Duobi's associate Kangsumi () surrendered to Li Jing, taking Empress Xiao and Yang Zhengdao with him. Emperor Taizong's official Yang Wenguan () wanted to have Empress Xiao interrogated as to whether any Tang officials had been secretly in communication with her, but Emperor Taizong refused and instead treated her with respect. Yang Zhengdao was given an honorific official post. As Empress Xiao's brother Xiao Yu was an important official under both Emperors Gaozu and Taizong, she maintained some degree of honor at the Tang capital Chang'an, and she was subsequently in charge of Emperor Yang's reburial with honor. She died on 17 April 648 in Chang'an and was buried with honors due an empress, at Jiangdu with Emperor Yang.