The dinner, dubbed “the most expensive in the country”, saw 200 business people and representatives gather in Addis Ababa.
Guests paid $173,000 (£136,000) to dine at the former emperor Menelik’s palace.
Since coming to power last year, Mr Abiy has pushed for wide-scale economic reform in Ethiopia.
The glitzy event was held to help pay for the regeneration of an area in the capital, Addis Ababa.
Beautifying Sheger, as the project is called, involves cleaning the rivers and building recreational parks in the capital.
Who was there?
Some 200 business people and representatives from different organisations attended the dinner, held in the lavish palace of a former emperor.
Guests began arriving at 15:00 local time (10:00 GMT) and were given a tour of the palace, according to some of the attendees who spoke to the BBC.
After the tour, they attended a cocktail reception and were personally greeted by Mr Abiy.
“I was happy to take pictures with him [Prime Minister Abiy Ahmed] and to talk to him like a normal friend. Not just me, but everybody else [got to experience that],” one guest, Ali Hussen, said.
He felt proud to be able to help his city:
“I don’t know how much money they collected [from the dinner]. But I am ready to pay again and again to finish the project”, Mr Hussen said.
The guests described the food as traditional.
“There was raw meat. And I appreciate the way they prepared it. There was Tej (honey wine), coffee, very special coffee,” Mr Hussen said.
Businesswoman Solome Tadesse said Mr Abiy was making the rounds to the tables, encouraging people to eat. According to her, the prime minister did not sit in a special place but sat among the guests and ate and drank with them.
“We were satisfied by a lot of things, not just the dinner. I came out with hope,” Ms Tadesse said.