Deulofeu spent last season at Everton, scoring three goals in 25 appearances in the Premier League and returned to Barcelona this summer looking for first-team opportunities.
But after coach Luis Enrique decided another campaign on loan would be beneficial, a deal was reached with the Europa League winners.
Sevilla confirmed on Thursday that the loan has been agreed and will go through ahead of the new league campaign.
"FC Barcelona and Sevilla FC have reached an agreement for the transfer of Gerard Deulofeu to the Andalusian club for the 2014-15 season," the statement read.
Deulofeu has played six times for Barcelona, with two of those appearances coming in La Liga.