He was the proprietor of a furniture shop and the property developers in Central District on Hong Kong Island.

[1] He used to be the director of Tung Wah Hospital.

[2] In 1912, Au went into partnership with his son-in-law's father Sir Kai Ho to form a company to develop a piece of land formed by land reclamation in Kowloon Bay.

It was planned to build a residential garden estate, but the plan failed and the company went into liquidation in 1924, after both Au and Ho had died.

[1] In 1925, the land was taken over by the British Hong Kong Government as the use of the airport.