The current research work focuses on how to improve the sensitivity and linear response of Fabry Perot(F-P) sensor, while the directional response of the sensor is less studied in partial discharge location. The directional sensitivity of F-P acoustic sensor based on micro electro mechanical system(MEMS) is experimentally studied. The thickness of diaphragm is 5 μm, and the acoustic signals from discharge sources with different incident angles and linear distances are measured and analyzed. The experimental results show that the sensor has 5.90 dB amplitude fluctuation and high signal-to-noise ratio in the incident range of ±60°, which makes it capable of detecting weak partial discharge signals beyond 3 m.