The tournament featuring Zimbabwe, Kenya, Namibia, hosts South Africa and 12 CSA affiliates will run from September 4 to October 4.
The CSA announcement today came in the wake of news that the T20 Champions League has been called off for this year amid declining revenues.
CSA said the tournament will be a World Cup-style competition, consisting of four pools of four teams each with the winners of each pool advancing to the semi-finals and eventually to the final.
"This tournament is an exciting new concept for our cricket," said CSA Chief Executive Haroon Lorgat.
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"It should provide impetus at the start of a season with exciting and competitive playing opportunities plus revenue generating potential for each team.
"We are keen to lead the way in developing an Africa-wide competition.
"With international Twenty20 matches to follow against England and Australia later in the season, this tournament will provide an early start for players to stake a claim in next year's ICC World Twenty20 squad.
"A key differentiator is for each team to include two under-21 players which will give rising stars the chance to play with our fully fledged professionals.
"Sides will be limited to fielding only one Proteas player each.
CSA also announced the appointment of former Proteas paceman Makhaya Ntini as the Africa T20 Cup Ambassador.
"I am both delighted and honoured to be invited to fulfil this role," Ntini said.
"The development of African cricket is something that is very close to my heart and I welcome this important initiative," he added.