As a footballer he played his whole career for Guangzhou F.C., where he was Nicknamed "Dwarf Tiger" because of his short sature, while internationally he was called up to the Chinese national team, where he took part in the 1984 Asian Cup.
He had to retire early in 1986 due to injury and moved to Japan to become the coach of Mitsubishi Motors F.C.
Zhao Dayu studied within the specialist sport schools within Guangzhou before being picked up by Guangzhou F.C., where he showed himself to be a technically gifted player before going on to break into the senior team and soon help guide the club to win promotion to the top tier when the club won the 1981 division title.
[5] It turned out to be the highlight of his career, and in 1986 he had to retire after he was unable to overcome a persistent tibia and fibula fracture in his left leg.
He is also the owner of a sportswear company named Ucan which had secured a kit sponsorship deal with China League One club Guangdong Sunray Cave.