Ex-boxing champ -- turned "Dancing with the Stars" contestant -- Victor Ortiz struck a plea deal in his DUI case ... and he's on thin ice for the next 3 years.
TMZ Sports broke the story ... Ortiz was arrested on Sept. 24th in Ventura County, CA around 7 PM when cops pulled over his BMW and smelled booze.
Officials say Ortiz's BAC was MORE than .15 ... which is a huge deal because in California, that triggers a "special allegation" which carries a tougher penalty if convicted ... more jail, higher fines, etc.