Abstract: This article covers a brief introduction about the test of overall heat transfer coefficient of Dongxin oil pipeline. Based on the pipeline operation parameters measured from the test, the overall heat transfer coefficients in each month of a year are calculated. The influences of various factors upon test results of overall heat transfer coefficient are analyzed. It is pointed out that the stability of pipeline operation conditions, temperature drops between heater stations, and measuring accuracy of temperatures are main factors affecting the test results, and frictional heat can significantly influnce calculation results of the overall heat transfer coefficient and can not be neglected. Some proposals for improving the test precision are put forward.