Emergency services were called to the development on Tuesday, September 4 over reports of a man who had been injured.
It is understood he had fallen from a ladder.
He was taken to Aberdeen Royal Infirmary for treatment, but Police Scotland said on Monday that 51-year-old Kevin Stewart, of Ellon in Aberdeenshire, had died.
Detective Inspector Allen Shaw said: “Our enquiries are continuing, with officers working alongside the Health and Safety Executive.
“Our thoughts are with the family of this man at this very sad time.”
The £333 million development in Bucksburn - replacing the current AECC - is to be named The Event Complex Aberdeen and is due to open some time next year.
A spokeswoman for Robertson, the group behind construction of the development, said: “We are devastated by the news that Kevin Stewart, a contractor who was working at the new AECC site, has passed away over the weekend.
“Our thoughts are with his family, friends and colleagues at this very difficult time.
“The Health and Safety of all our employees and contractors remains our top priority, and we are committed to supporting the ongoing police and Health and Safety Executive investigation into the incident.
“Employees on the AECC site who feel affected by this tragic incident have been offered the use of a free counselling service, which is open to all employees.”