With the development of dredging industry and environmental protection requirements in the world, trailing suction hopper dredger will face more long-distance, deep-sea and far-sea projects in the future.In view of the problem that the cost of transportation and navigation greatly increases in such projects, we take “Tongtu” ship as an example according to the theory of absolute economic speed and relative economic speed, use the load characteristic curve of diesel engine and the construction characteristics of trailing suction hopper dredger, analyze the data relationship among the load, oil consumption, production value, cost and other indexes in the process of transportation and navigation, and form the real ship calculation model when carrying and sailing under the working condition based on the relationship curve.The results show that the calculation model is helpful to make full use of the economy of the trailing suction hopper dredger in the long distance and far-sea engineering, and improve the engineering benefit.