and Du successively served as Gongbu Langzhong again and then as Jinbu Langzhong (), a supervisorial official at the ministry of census (戶部, Hubu). In 780, Yang also had Du made the director of food supplies from the Yangtze River and Huai River regions. He later served in another supervisorial position at the ministry of census — Duzhi Langzhong (), before being promoted to be the deputy minister of census (戶部侍郎, Hubu Shilang), in charge of the financial matters of the state. With Emperor Dezong waging multiple campaigns against warlords ruling their circuits in de facto independent manners at the time, Du was forced to raise taxes heavily and force merchants to lend one quarter of their assets to the state to cover the expenses. Du would become despised by Yang's successor as primary chancellor, Lu Qi, and Lu had him sent out to be the prefect of Su Prefecture (蘇州, in modern Suzhou, Jiangsu). Du declined the assignment on account that his mother was still alive and the previous prefect of Su Prefecture had to leave office when his mother died. He was then made the prefect of Rao Prefecture (饒州, in modern Shangrao, Jiangxi), and soon thereafter the military governor of Lingnan Circuit (嶺南, headquartered in modern Guangzhou, Guangdong). Up to that point, the military governor of Lingnan customarily also carried the title of director of five special districts that Lingnan was divided into — one of which was Rong District, which Du had previously governed. Because Emperor Dezong had been forced to flee Chang'an due to a rebellion by Zhu Ci in 783, however, the officials at his makeshift court did not have full knowledge about precedents, and Du became the first military governor of Lingnan not to also be director of the five districts. In 787, Du was recalled to Chang'an to serve as Shangshu Zuo Cheng (), one of the secretaries general of the executive bureau of government (尚書省, Shangshu Sheng). He was later made the governor (觀察使, Guanchashi) of Shan Prefecture (陝州, in modern Sanmenxia, Henan) and then the military governor of Huainan Circuit. While he was serving there, his mother died, but Emperor Dezong recalled him from his mourning period to continue his service. In 800, after Zhang Jianfeng the military governor of neighboring Xusihao Circuit (徐泗濠, headquartered in modern Xuzhou, Jiangsu) died, the soldiers of Xusihao assassinated the acting military governor Zheng