Pc Keith Wallis, 53, from West Drayton, west London, is accused of committing misconduct in public office by saying he had witnessed the incident and arranging for his nephew to support the claim. Mr Wallis attended a hearing at Westminster Magistrates' Court.
He is facing claims that he emailed Tory deputy chief whip John Randall, who was his MP, wrongly claiming he had seen what happened in Downing Street on September 19 last year.
A row erupted when then-chief whip Andrew Mitchell became involved in a heated confrontation with another officer, Toby Rowland, after he was refused permission to cycle through the main gate.
Mr Mitchell admitted swearing but denied he used the word "pleb".
Mr Wallis, from the Metropolitan Police Diplomatic Protection Group, was released on bail and will next appear at Southwark Crown Court on January 3.