Eu takes over the role from Brian Gaffne, who will retire at the end of the year, the firm said.
Ng will take charge of his role from January 2016. He will also join the firm’s global executive committee.
Ng is currently the head of institutional business in Asia-Pacific and chief executive for Greater China and Southeast Asia.
He joined Allianz Global from Invesco last year and has previously held senior roles at JP Morgan Asset Management.
"Doug [Douglas Eu] has done a tremendous job in establishing deep client partnerships and in so doing has built a fast-growing business in Asia Pacific,” said Elizabeth Corley, global CEO for the firm.
“We are confident that Desmond [Ng] is the right person to continue the growth and strategic development of our business in Asia-Pacific.”
Both Eu and Ng will continue to work closely to ensure a seamless transition, she said.
Eu joined Allianz Global Investors in 2006 from JP Morgan Asset Management, where he worked for 19 years.