The Senegal forward is the first Premier League player to be punished under the new Football Association laws, which were introduced in May.
Niasse won a controversial penalty, under pressure from Scott Dann, during Saturday’s 2-2 draw at Crystal Palace.
The 27-year-old will miss Everton’s game at Southampton on Sunday and at home to West Ham on 29 November.
Everton said they were “disappointed” with the ruling but have accepted the verdict and will review the FA’s written reasons, which are set to be published on Thursday.
Niasse denied he had “committed an act of simulation” that led to the penalty being awarded in the fifth minute of the game.
Leighton Baines converted from the spot, and Niasse later scored his side’s second equaliser at Selhurst Park.
The FA’s Independent Regulatory Commission, which includes former players, found the striker guilty of the charge when they met on Wednesday.
Incidents which suggest a match official has been deceived by an act of simulation are referred to a panel consisting of a former match official, ex-manager and former player.
They independently review video footage and the FA only issues a charge if the panel are in unanimous in agreeing simulation took place.
Carlisle forward Shaun Miller was the first to be banned under the new system, when he was suspended for two games in October.