While the officials Yuan Qianyao and Meng Wen (孟溫) successively served as the mayors of Jingzhao, both of them respected his abilities.
At that time, there were many people who tried to evade labor conscription and taxes by avoiding being enrolled on census rolls, or fraudulently claiming exemptions, causing a drain on the imperial treasury.
In 721, Yuwen requested that he be specially commissioned to go after census evaders and fraudulent exemption claimers, and, with support from Yuan, who was then a chancellor, Emperor Xuanzong agreed.
Subsequently, apparently at Yuwen's urging, Emperor Xuanzong issued an amnesty period for the census evaders to report themselves and allowed them to be exempted from retroactive taxation.
Emperor Xuanzong agreed and carried out the plan, despite objections submitted by the official Wu Jing (吳兢), although in 726 he stopped the scheme.
In 727, Emperor Xuanzong, tired of that situation, ordered Zhang Yue to retire, Cui to return home to serve his mother, and demoted Yuwen to be the prefect of Wei Prefecture (魏州, in modern Handan, Hebei).
It was further said that Yuwen was intelligent and capable in increasing revenues, drawing Emperor Xuanzong's favor, but was frivolous, talkative, and nepotistic, once commenting, "Let me sit on this seat for a few months, and the realm will have no troubles."
He demoted Yuwen to be the prefect of Ru Prefecture (汝州, roughly modern Zhumadian, Henan) -- after serving 100 days as chancellor.
Meanwhile, as Pei was also serving as chief imperial censor by this point, he submitted an indictment against Yuwen for corruption and improper association with others, and he was demoted to be the sheriff of Pingle County (平樂, in modern Guilin, Guangxi).
After he had spent more than a year at Pingle, the deputy minister Jiang Cen (蔣岑) further accused Yuwen of corruption while serving as prefect of Bian Prefecture.