Abstract: Distributed optical fiber temperature sensing is a cutting-edge technique in pipeline detection，which has not been used in China.This technology is a detection method based on the change of the temperature field around the space before and after pipeline leaks.It has a high accuracy in data transfer and read speed，and strong self adaptability，making it a great prospect.Before the implementation of the technology，the space temperature field before and after pipeline leaking should be studied.Using the finite volume method to build the mathematical model of the heat transfer in porous media when buried pipeline leaks.Using the FLUENT soft to numerical simulate the ground temperature change in different locations when oil pipeline leaks in winter and the law of the oil distribution in the soil.The comparison of the soil temperature field before and after the leakage show that in a certain period after the pipeline leaks，the soil temperature around the pipeline is volatile，and due to the environmental temperature，the temperature of the oil leaked first drops quickly to the freezing point，and forms different kinds of dynamic coagulation oil layers，resulting in the decreasing of the oil seepage rate，and the heat affected zone changes gradually to a stable state.In different locations of the leakage，the change of the surface temperature is big and the oil distribution in the soil is quite different.It is feasible to detect the pipeline leakage by using the distributed fiber optic temperature sensor.

Key words: buried pipeline, leakage, porous medium, thermal fluctuation, seepage