Research commissioned by the local authorities that neighbour Heathrow, has uncovered the job loss prediction.
The report concludes previous studies have underestimated the impact on employment if the airport were to shut.
An interim report on airport expansion by the Airports Commission will be published next week.
In October, the commission said additional runways would be needed in the south east but did not specify their location.
One of the options under consideration is a new hub airport with four runways to the east of London, backed by London Mayor Boris Johnson.
A transport think tank has stated the only way such a new hub could operate would be if Heathrow closed down.
The councils said they were concerned the local impact of any decisions affecting Heathrow was not being given sufficient weight by the commission.
It currently employs between 10% and 29% of each borough's workforce, they said, and as many as 250,000 jobs across west and south-west London would also be at risk.
The report also warns moving the location of the UK's hub airport could lead to the IT and telecommunications industry in Hounslow, Slough and neighbouring boroughs relocating, possibly outside the UK.
"At a time when the UK's economic recovery is in its fragile infancy and needs to be nurtured, it would plunge west London into a new recession from which it might never fully recover," Colin Ellar of Hounslow Council, said
Replacing Heathrow with a new hub airport would put up to 70,000 local jobs at risk, Slough, Ealing and Hounslow councils have warned.