The 43-year-old ex-Manchester City and Newcastle midfielder appeared via videolink from Liverpool prison for the plea hearing at Liverpool Crown Court on Tuesday.
He pleaded not guilty to causing grievous bodily harm with intent to Kevin Lynch, 51, at Fairway in Huyton near Liverpool, on March 8th.
Barton's co-defendant, Gary O'Grady, 50, of Huyton, was not asked to enter a plea to the charge on Tuesday.
An earlier court hearing was told the defendants had been drinking with Lynch at Huyton and Prescot Golf Club before the alleged attack.
Lynch, a former non-league football manager and founder of special education school NexGen Academy, was said to have suffered serious injuries to his eye.
Judge Andrew Menary set a trial date of September 1st, with the case expected to last seven days, during a 15-minute hearing that also dealt with administrative matters.
Barton, of Widnes, northwest England, was remanded in custody, while the judge renewed conditional bail for O'Grady - supported in court on Tuesday by several family members.
Barton won one England cap during a playing career that also included stints at Scottish giants Rangers and French club Marseille.
He now hosts podcast Common Sense With Joey Barton, which is described as an "unfiltered" look at issues in sport, society, politics and other topics.