Attorney Cyrus Nownejad told The Associated Press that Tequila is seeking $1.5 million in damages.
Merriman was arrested by sheriff's deputies on Sept. 6 after Tequila signed a citizen's arrest warrant accusing him of battery and false imprisonment at his suburban home. District Attorney Bonnie Dumanis declined to charge Merriman.
Merriman told the AP in an e-mail that he hadn't seen a copy of the suit. His attorney didn't immediately return a call seeking comment Tuesday.
Tequila, whose real name is Tila Ngyuen, alleges assault, battery, false imprisonment and intentional infliction of emotional distress.
She said that when she tried to leave his house, Merriman grabbed her by her arms. When she tried to break free, Merriman shook her like a rag doll, the suit said.
Merriman threw her onto a couch, hurting her neck, jaw and back, then choked her until she almost passed out, the suit alleges.
Tequila said in the lawsuit that Merriman had a short temper, used drugs and humiliated her because of her bisexuality.
The lawsuit includes two exhibits of photos, including photos purporting to show bruises on Tequila's arms and neck.
Dumanis decided not to charge Merriman after her office spent three days reviewing reports from the San Diego County Sheriff's Department.
"After a thorough review of the investigation into the Sept. 6, 2009, incident at the Poway home of Shawne Merriman, our office has determined there is insufficient evidence to prove beyond a reasonable doubt that any crime was committed," Dumanis said in a statement. "This case is now closed. No further comment will be made."
Tequila is best known for "A Shot at Love with Tila Tequila," which ran for two seasons on MTV. The bisexual dating show featured men and women vying for Tequila's affections. She has also modeled for Playboy and other men's magazines.
Merriman said he was trying to keep Tequila from leaving his home because she appeared to be intoxicated, and denied harming her.
Information from The Associated Press was used in this report.