It is presumed that she survived, because she was not one of the people in the line of the dead. Although she was seriously injured, as Finrir Grayback jumped and landed on her from a tall staircase. She was saved when Hermione Granger cast a spell amd then Professor Trelawney dropped a crystal ball on his head knocking Greyback unconscious. Lavender was feebly stirring.
However, in the film, Greyback killed Lavender.