Abstract: Based on the heat equilibrium analysis, the critical conditions by non-heating transportation for oil pipeline are outlined in this paper. The analysis results show that these conditions, including critical velocity of flow and heat transfer coefficient, are related to the soil nature in the place where pipeline is embedded and the temperature difference exists between oil and soil. They are also related to the discharge rate and oil physical characteristic within pipeline. The critical velocity of flow is in direct proportion to the cube root of the product that the heat transfer coefficient times the temperature difference between oil and soil. The critical heat transfer coefficient is in direct proportion to the cube of flow velocity and in inverse proportion to the temperature difference between oil and soil. The lower the critical velocity, or the higher the critical heat transfer coefficient, the greater is the possibility that non-heating oil transportation will be put into practice. The friction heat converted by water head loss during transportation will be rising and the temperature drop down if the discharge rate becomes larger. It is beneficial to upgrading operation economics for oil pipeline designer to adopt higher velocity and make pipeline good heat preservation condition.