The 25-year-old will undergo a medical in Spain before swapping Yorkshire for Catalonia permanently in a deal believed to be costing Barca £58m.
Raphinha scored nine goals in 27 Premier League appearances for Leeds last season and made his senior debut for Brazil in October.
Chelsea had been interested in the winger, but has only had eyes for Barca and will sign a contract until 2027.
Club president Joan Laporta said the deal is likely to be concluded this week and said that Ousmane Dembele will sign a new contract.
Barcelona are still chasing Robert Lewandowski from Bayern Munich, which would form a very dangerous attack with Pierre-Emerick Aubameyang also there.
Frenkie de Jong is one name on his way out, with Manchester United keen.
Barca are known to be suffering from financial difficulties and former Leeds defender Danny Mills hopes the club will see the money for Raphinha soon.
"Leeds just need to see the cash now," he told Kick Off on talkSPORT.
"It's bizarre, isn't it? Barcelona are skint, can't register players but they're still buying players for ridiculous amounts of money.
"This move could fall through, you need to see the colour of money… it seems like monopoly money Barcelona are using."
French side Rennes signed Raphinha from Sporting Lisbon in 2019 and then moved to Leeds for £17m in 2020.
Last season he helped the club avoid relegation from the Premier League.