Born in Lotian (羅田, now in Hubei), Xu was a cloth vender by profession. In August 1351, he worked with others in in Qizhou (蘄州) to establish the rebel army of Red Turbans under the pretense of the Buddhist White Lotus Society. In the following months, they captured Qishui (蘄水) and made it the command centre of the Red Turbans and the capital of the newly declared Empire of Tianwan (天完), with himself as the emperor with the era name of Zhiping (治平).
The number of his supporters increased rapidly as he claimed to be a Milofo reincarnate (彌勒佛下生) who sought to "destroy the rich to benefit the poor" (摧富益貧). In 1352, he invaded more of Hebei, and moved on to take Jiangxi, Anhui, Fujian, Zhejiang, Jiangsu, and Hunan.
After being temporarily defeated by the Mongol army, he fled to Huangmei Mountain (黃梅山). He returned in 1355 to invade once again and moved the capital to Hanyang.
After he was murdered by Chen Youliang, his former co-fighter, Tianwan Empire collapsed.