The focus of the meeting of heads of state from the 54 member nations is expected to be on promoting and facilitating trade among countries on the continent.
Delegates are also due to elect a new head for its secretariat, the AU commission, as well as new members to lead the Peace and Security Council, which enforces AU decisions.
AU commission chairman Jean Ping, who is running for re-election, is being challenged by South African Home Affairs Minister Nkosazana Dlamini-Zuma.
UN Secretary General Ban Ki-moon is scheduled to attend.
The modern 100-metre high AU skyscraper is to be inaugurated Saturday. The 200-million-dollar project was funded by the government of China and designed by the Shanghai-based Tongji Design Institute.
The building consists of several conference rooms, a library, media centre, as well as banks and other businesses. – Sapa-dpa