To meet the need of the pressure measurement in high temperature oil wells,an extrinsic Fabry-Perot(F-P)interferometer(EFPI)based optical fiber pressure sensor is developed.The F-P cavity sensor fabricated by laser thermal bonding technique has characteristics of large dynamic gauge range,low temperature sensitivity,high temperature resistance and long term operation stability.The pressure resolution of 0.03 MPa over the full scale from 0 to 30 MPa has been achieved.Solutions for some key problems in the downhole measurement have been proposed:by optimizing the structure of the F-P sensor the cross-sensitivity of temperature and pressure is effectively reduced;for prolonging the life time of sensor head and polyamide coated fiber an epoxy-free package method based on hermetical bonding of quartz ferrule and fiber is used.The sensor system has been successfully applied to downhole pressure measurement in Liaohe oil field.