The suspect, 20-year-old Paul Meyer, is now behind bars facing a charge of attempted murder.
Police say the trouble broke out around 2:30 a.m. Friday. Police say Meyer and the woman knew each other. There was some sort of altercation and the 20-year-old allegedly tried to strangle the woman. The victim was taken to the hospital where she was treated and released.
This isn't the first time Theta Chi has had serious trouble during a party. Two years ago, an 18-year-old man, who was not a UCLA student, died during a party at the fraternity house of a suspected overdose.
Police are investigating if alcohol may have played a part in the early-morning assault.
It is unclear if Meyer lives at the fraternity house or is just a member.