As a well-known means for pumping crude oil with high pour point, the economic effect of a hot oil pipeline to be built will depend on such factors as pipeline capacity, pipeline length, properties of the oil to be pumped, environmental conditions along the right of way, design scheme and operation scenarios. Generally speaking, engineering-economic characteristics of oil and gas pipelines are a complete set of the economic relationships relevant to engineering factors of the pipelines, each relationship involving at least an economic index or parameter. The engineering-economic characteristics of hot oil pipelines reflect basic regularities governing the general economic effect and each economic index of the pipelines, so it is helpful understanding these characteristics for the decision-making about whether and how to build a hot oil pipeline. In some cases, for a specific hot oil pipeline project, a decision or judgment on macro level may be made only from some common engineering-economic characteristics of hot oil pipelines, without the need for the engineering design and the economic analysis of the project in detail. The frame of engineering-economic characteristics of oil and gas pipelines is outlined in this paper, and some key elements are discussed on the basis of a large amount of engineering calculation and economic analysis of virtual hot oil pipeline projects, including the optimal pipe diameter and the optimal flow velocity for a given pipeline capacity, the economic capacity limits and the economic flow velocity limits for a given pipe diameter, the economically feasible maximum pipeline length for a given pipeline capacity, and the economically feasible minimum pipeline capacity for a given pipeline length. Though the basic economic data used in our research come from China, its research results and conclusions on engineering-economic characteristics of hot oil pipelines also would be helpful for hot oil pipeline projects in other countries all over the world.