After Xuande's unexpected death in 1435, their son Yingzong ascended the throne, and Sun became the empress dowager (). A day before he died, Xuande issued instructions that the civil and military officials should guide the child, and they should petition his mother, Empress Dowager Zhang and Sun on all important matters of the family and state. She and her mother-in-law openly vied for supremacy. Ultimately Zhang prevailed and sidelined Sun. Sun tried to influence certain government matters, and the imperial historians censured her, a custom acted to restrain palace women. After Zhang's death in 1442, Yingzong began to manage the matters himself. In 1449, he foolishly decided to lead a military expedition against the Mongols, and ended up being captured. Sun and his consort
Empress Qian immediately raised a ransom in jewels, and sent it off to secure his release. At first it was decided that the court should retreat to the south. However, Li Yongchang won over the empress, and
Yu Qian's party won the day, according to whom that those who advocated retreat should be executed. The officials despised Yingzong, and decided to make his younger brother Jingtai Emperor. He was first instructed by Sun to take charge of government affairs as regent, while the emperor's one year old son was made heir apparent. On 15 September 1449, with Sun's assent, he was urged to ascend the throne in person, since the emperor was in captivity and his one year old son was incapable of ruling. He at first refused, since it would confuse the dynastic succession. Only after Sun's approval and Yu Qian's advocacy of the urgent national need for leadership eventually persuaded him. On 23 September, only three weeks after the emperor's capture he ascended the throne, and the captive emperor was given the title of retired emperor. Sun was given the title of high and sacred empress dowager (). The Mongols soon released Yingzong, knowing that the presence of two emperors would cause instability among their enemies. He was initially placed under house arrest. Six years later in 1457, Sun and her brothers lead a coup that dethroned Jingtai, and placed Yingzong back on the throne. She was given the title of
Empress Dowager Shengliecishou (). ==Death==