The application of reflection-type nematic liquid crystal(NLC) infiltrated photonic crystal fiber(PCF) as a sensor for electric field intensity measurements is demonstrated.The sensor probe consists of a section of infiltrated photonic crystal fiber with length less than 1 cm.We coated silver film on the bottom of infiltrated photonic crystal fiber in order to enhance the reflectivity.The electric field dependent reflection intensity at 1 550 nm wavelength is experimentally discussed.And it also confirms that these structures can be used to accurately measure the electric field intensity(1.4-3.7 kVrms/mm).The experiment results show the impacts of Ag coating on reflection intensity,sensitivity and measuring accuracy of the sensor.