Mr Ize-Iyamu, who enjoys the support of the embattled national chairman of the APC, Adams Oshiomhole, defeated two other aspirants – Pius Odubu and Osaze Obazee – to win the primary.
The direct primary was reportedly conducted in the 18 local governments of Edo State.
In the result announced by the Imo State Governor, Hope Uzodinma, Mr Ize-Iyamu scored 27,833 votes while Mr Odubu, the former deputy governor of the state, came second with 3,776.
Mr Obazee garnered over 2,000 votes, said Mr Izodinma who is the chairman of the primary committee of the party.
Mr Ize-Iyamu, who was the opposition PDP governorship candidate in 2016, will now fly the flag of the APC in the September governorship election.