Abstract: Photonic crystal fibers (PCFs) have many unique advantages as a new generation of optical fibers when compared with conventional optical fibers. Hence, study on fiber-optic sensors based on PCFs has become one of the hot topics in the field of optical fiber sensing. In this paper, a series of fiber-optic Fabry-Perot interferometric (FFPI) sensors based on PCFs are reported for the first time to our knowledge, including FFPI strain and temperature sensors based on hollow core PCF; FFPI temperature and refractive index sensors based on solid core single-mode PCF; FFPI high temperature strain sensor based on solid core PCF fabricated by fs and 157nm lasers. These novel PCF-based FFPI sensors have many outstanding advantages, such as insensitive to temperature change, high accuracy, good reliability, capability to operate in harsh environments, etc. It is anticipated that they would find important applications in many areas, such as energy, transportation, aerospace, biochemical, etc.