Abstract: Oil in pipeline has complicated heat-history and shear-history, which can be simulated only by instrument of pipe-flow if similarity is considered. In this paper, the instrument was used to measure the curve of viscosity-temperature, influnce of rate of decreasing temperature, influnce of repeated heat treatments and influnce of pipe diameter. It has been found that the rate of decreasing temperature has great influnce on viscosity-temperature property of the oil below abnormal point; the repeated treatments have no effect on the property; the different diameters, resulting in different history, have some effect on the property of cold oil.