The non-steady state heat transfer calculation model for forward and reverse pumping is established according to reasonable simplified assumption in this paper.Then solve the temperature drop in the reverse transportation on the basis of verifying the reliability and accuracy of steady-state operation in forward transportation.Innovatively, the reverse transportation temperature drop process can be divided into initial stage of reverse transmission, control stage of cold oil head, control stage of hot oil head, and steady stage of reverse transportation temperature drop.Detailed analysis on the effect of outlet temperature, reverse flow rate, buried temperature and pipe diameteron the temperature drop in the four stages has been performed.The results shows that increasing the reverse flow has the most positive effect on the forward and reverse pumping, and that it is easier to execute the reverse transportation in the summer.The use of small-diameter pipelines for reverse transportation will take a relatively short time to reach steady stage.This result will provide certain basis for more rational arrangements for forward and reverse transportation plans in the future.