Jamie Cox was sentenced to 26 weeks for common assault after he attacked Viktoria Gribovskaja at her home in Lambeth, south London last year.
The Swindon-based WBO European super-middleweight title holder had denied assault.
His sentence was suspended at an appeal at Croydon Magistrates' Court.
The 29-year-old boxer, who appeared in court under his real name Jamie Russan was told his conviction still stands, but that his prison sentence will be suspended for 18 months.
Recorder Joseph Boothby told him he should treat the suspended sentence as "a turning point" and said: "Change your ways and think before you get angry with a girlfriend, or anyone else for that matter."
Cox had been sentenced to 26 weeks in prison for the assault and harassment charges, 20 weeks for violence to secure entry and 12 weeks for criminal damage, to run concurrently.
He is currently ranked number four in the world and is also a Commonwealth Games light welterweight champion.
After the hearing, Cox said: "I just want to get back to normal and to fight for world titles. I do not really treat today as a success."
A champion boxer who was jailed for breaking into his ex-girlfriend's flat and attacking her has had his sentence suspended.