The Hammers will pay £2.5m rent annually but will not have to fund police, stewarding, heating, pitch maintenance, or even corner flags.
"My dog could have negotiated a better deal for the taxpayer," said Hearn.
West Ham said it was "a great deal" for the club and the public.
The Premier League club move to the 60,000-seater stadium from the Boleyn Ground, which has a 35,000 capacity, at the end of this season.
Olympic Stadium bosses, the London Legacy Development Corporation (LLDC), fought a ruling that the deal should be published, but the appeal was rejected this week.
On Thursday, full details of the 207-page contract were published for the first time, including that:
West Ham have paid £15m towards the £272m costs of transforming the stadium into a football venue.
Hearn, who unsuccessfully tried to get the Hammers to groundshare with Orient at the Olympic Stadium, told BBC Sport: "It's a hugely beneficial deal to West Ham and good luck to them.
"They've negotiated a good deal. I can't say the same for the LLDC who should go back to negotiation school.
"Frankly it was a hot potato that [London mayor] Boris Johnson and the LLDC wanted to get rid of. They wanted to close a deal at any price and they will say 'quite rightly because we didn't have anyone else'."
The LLDC fought publication on the grounds of commercial sensitivity and fear the decision to publish will cost it million of pounds in lost revenue.
"The stadium needs to be a profitable and successful commercial operation, otherwise it will rely on public subsidy," said a spokesperson.
West Ham insist the club have nothing to hide and believe their position as anchor tenant helps ensure the stadium does not become a "white elephant".
"We were unanimously chosen as the anchor tenant, above others, including football clubs such as Tottenham Hotspur and Leyton Orient, as we offered the best deal and the only option for a true and lasting legacy," said a Hammers statement.
The deal was published after a lengthy legal battle following an initial freedom of information request from an alliance of 14 supporters' groups.
"This is a victory for the power of football supporters - organised, focused and willing to work together to achieve a collective goal," said a coalition statement.
Aside from West Ham, who will rent the venue for 25 days a year, the venue will host concerts and other sporting events, including the IAAF and IPC Athletics World Championships next year.
Former Leyton Orient chairman Barry Hearn says his dog could have negotiated better than venue bosses after details of West Ham's Olympic Stadium contract were published.