The Seville club's ground, with a capacity of almost 61,000, was chosen ahead of Valencia's Mestalla home for the right to stage the game.
Last year's final was played at Atletico Madrid's Wanda Metropolitano, where Barcelona beat Sevilla 5-0 to win the trophy for the fourth season in a row.
It is the first time the venue for the final has been announced before the finalists are known.
This season's competition is at the quarter-final stage, with the second legs due to be played this midweek.
Betis are still in the tournament, having drawn 1-1 away to Espanyol in the first leg last week.
It will be the fourth time that the Copa del Rey final has been played in Seville, but the first at the home of Betis, who are two-time winners of the trophy.