The concept of material transportation radius for straw-energy engineering, proposed in line with the regional characteristics and project types, is of great significance in promoting engineering economic efficiency and ecological environmental protection. Taking the concept as the core, straw energy conversion density and the evaluation model for engineering economy and environmental efficiency have been put forward, with the evaluation indicators including economic units and the reduction potentials in the emission of greenhouse gases and PM 2.5. An economic and environmental evaluation of the straw transportation radius in Harbin region has fully demonstrated that Harbin, the most advantageous region in Heilongjiang Province in developing straw-energy engineering, embraces the economically optimized straw transportation radiuses of 37, 5,2 km, and 4 km respectively for the development of straw-gasification, -ethanol, -based heat and power cogeneration and -briquetting production projects. Meanwhile, in view of environmental benefits, the descending order of the 4 types of energy engineering are straw-gasification, -ethanol, -based heat and power cogeneration and -briquetting production projects.