The US Open champion Stosur had to fight hard for her victory in the semis as she defeated China’s Zheng Jie 7-6 (5), 3-6, 6-3.
The Australian will be aiming to win her fourth career title.
She will meet Marion Bartoli in the final. The French eliminated the German Angelique Kerber 6-1, 7-6 (5).
In their last encounter in Eastbourne this year, Bartoli beat Stosur in straight sets.