In order to meet the requirement of oil well safety fabrication and temperature monitoring of heavy oil

design a kind of distributed optical fiber temperature sensor with a sensing distance of 2km to monitor temperature of oil well of heavy oil. Characteristics analysis is carried out and high temperature experimental results are given.The results show that distributed optical fiber temperature sensor can play an important role in oil field temperature measurement. Its temperature range is 0

350 ℃

range of optical fiber length is 2km

temperature precision is± 1℃

and spatial resolution is 1m

which provides scientific data for measurement of temperature under oil well.