Xu's surname is one of the surnames in China, which mainly comes from the surname won and the surname changed by ethnic minorities. Xu Ruomu is the ancestor of Xu in Xia Dynasty.
Xu was ranked150th in the Song version of Hundred Family Names. By 202 1, according to the data of the National Bureau of Statistics, Xu was ranked 1 1 (20th in Taiwan Province Province, China), with a population of nearly 20 million.