By TMZ

Former four time heavyweight champion Evander Holyfield is staring down some jail time if he doesn't cough up more than $300,000 in unpaid child support, TMZ has learned. The Georgia Dept. of Human Services has gone to court on behalf of Evander's 18-year-old daughter Emani Holyfield ... claiming the former champ hasn't paid any court ordered child support since April 2010, and his tab is now $372,097.40.

The Dept. of Human Services is fed up with the waiting game ...  so it's asking a judge to lock up Holyfield and garnish his wages until he antes up the back support.

Evander's rep tells TMZ she was unaware of the situation but added, "Mr. Holyfield has a wonderful relationship with his daughter."