The full-back, who will put pen to paper on his new deal in the coming days, will be tied to the Spanish champions until June 2020.
Alba has made 43 appearances for Luis Enrique???s side this season, including last weekend???s triumph over Athletic Bilbao in the Copa del Rey final.
He featured in both legs of the Champions League semi-final against Bayern Munich, and is set to play a part in Saturday???s final in Berlin, when Enrique???s men take on Juventus.
The 26-year-old moved to the Nou Camp from Valencia in 2012 for ??14m and has 33 Spain caps to his name.
The defender???s contract will also include an increased buyout clause of ??108m.