Barjuan will step up from his role as Barcelona's B team boss and will take training on Thursday before facing the media on Friday.
The Catalans parted company with Ronald Koeman on Wednesday following a 1-0 defeat to Rayo Vallecano in La Liga.
The defeat left Barcelona in ninth position, six points behind leaders and bitterest rivals Real Madrid.
A statement on Barcelona's official website read: "FC Barcelona hereby announces that Sergi Barjuan, the current coach of Barça B, shall be taking provisional charge of the technical management of the senior squad. His interim position as first team head coach shall end as soon as the club has hired full-time head coach to replace the dismissed Ronald Koeman."
"FC Barcelona president, Joan Laporta, shall be officially introducing Sergi Barjuan to the first team squad this afternoon before the training session at the Ciutat Esportiva."
"Sergi Barjuan will be attending to the media tomorrow from 1.00pm CEST in the pressroom at the Ciutat Esportiva to discuss the game against Alavés, with president Joan Laporta also appearing."
Barjuan is a former Spain and Barcelona left back who won three La Liga titles and two Copa del Reys in a nine-year spell with the Camp Nou outfit.
Barcelona have been linked with an approach for their former player Xavi Hernandez to take over on a full time basis.
Xavi is currently managing Qatari side Al Sadd.
