Im and his South Korean team mates, Kim Bub-min and Oh Jin-hyek, also broke the team world record for 72 arrows with a score of 2,087 at Lord's Cricket Ground.
Im's achievements are all the more remarkable when you consider that he is legally blind.
Im is afflicted with severe myopia that makes his sight 20/200, roughly 10 times worse than a normal person's.
In technical terms, that makes him legally blind. In practice, it means he can't read the letters on a keyboard, for example - and all he sees down the end of the archery range is a small blur of colour.
Im, who won team gold at the 2008 and 2004 Games, lost his world number one ranking to American Brady Ellison in 2011 but has been in sensational form in the lead-up to the London Games, winning the test event at Lord's late last year and setting the previous record of 696 in Turkey in May.
The Korean, was happy to be at the top of the ranking round but was not about to get carried away.
"It's just the first round so I won't get too excited about it," he said.
Im will face 64th ranked archer Emanuele Guidi of San Marino in the first round. Guidi scored 110 points less than Im.
Im's team mate Kim would also have broke the record after shooting 698, while the third member of the team Oh finished with 690.
South Korean head coach Jang Young-sool was delighted his team had shot so well in the ranking round and said the damp drizzly conditions had not been a problem.
"It was good weather to shoot," he said. "A world record gives us confidence for the rest of the competition."
Despite winning the last three team gold medals, South Korea's men have yet to win the individual title.