The research, by accountancy firm EY, predicts the tournament will attract a total of 466,000 visitors, who will spend as much as £869m.
The 2015 Rugby World Cup will be hosted in 11 cities across England and Wales.
In terms of single sporting events, only the football World Cup brings in more paid spectators, the report added.
Spending on food and drink by ticketholders will generate as much as £32m in revenue, EY calculated,  and a further £13m will be spent in "fanzones" - city centre shopping attractions with a Rugby World Cup theme.
The report also estimated the benefit to host cities of improved infrastructure, through investment in transport and stadia.
Debbie Jevans, who is in charge of England Rugby 2015, said the report proved that the tournament was "set to create a wide range of economic opportunities across many different sectors".
She added: "Whether through investment in infrastructure, supporting jobs or generating revenue in 'fanzones', the economic benefits will be shared around our 11 host cities and beyond."
Next year's Rugby World Cup will add £982m of value to the UK economy, says a report commissioned by the tournament's organising committee.