In China, the 33-year-old will link up with Argentine compatriot Ezequiel Lavezzi at a side coached by former Real Madrid and Manchester City boss Manuel Pellegrini.
Mascherano made 334 appearances in a successful spell at the Catalan side, lifting 18 major honours, including two Champions League triumphs and four La Liga titles.
"Javier Mascherano is leaving FC Barcelona after seven-and-a-half seasons. The Argentinian will be receiving an institutional farewell from the club on Wednesday," Barcelona said in a statement.
"The club president, Josep Maria Bartomeu and the first team squad will be present. The player will say goodbye to the fans on the pitch ahead of the club's King's Cup tie against Espanyol on Thursday."
Hebei, who finished fourth in last year's Chinese Super League, announced Mascherano's signing on their official social media account soon after Barcelona confirmed his departure.
"After discussions with FC Barcelona and the player, we hereby announce that the Argentina captain Javier Mascherano has officially joined Hebei China Fortune Football Club," Hebei said.
"He will wear the number 14 shirt in the new Chinese Super League season. We warmly welcome him and hope he can lead the team to a higher level."
Mascherano joined Barcelona from Liverpool in 2010 for a reported 22 million euros (19.26 million pounds) and was converted by coach Pep Guardiola from a holding midfielder into a centre back, often deputising for the injury-plagued Carles Puyol.
His departure also frees up the number 14 jersey made famous by Dutch great Johan Cruyff.
Spanish media have reported that recent arrival Philippe Coutinho -- who signed for a club record 142 million pounds, also from Liverpool, earlier this month -- will be handed the prestigious squad number.
Mascherano has signed a two-year deal with Hebei, with the Chinese club paying a fee of 5.5 million euros. The Chinese Super League season kicks off in March.
(Additional reporting by Michael Church in Hong Kong; Editing by John O'Brien)
