Today, the global ecological environment is deteriorating and building's impact on the environment is more and more noticed by people. This paper introduces a environmental cost analysis method. It can effectively convert emissions of pollutants into environmental cost, and reflects environmental performance from the economic point of view. This paper take global warming as study represent of the environmental problems, and take rural houses’ wall of Harbin as research objects, analyzing emissions of the four wall structures in their whole life cycles, namely the traditional 490mm thick solid clay bricks wall, EPS exterior insulation composite wall, EPS sandwich insulation composite wall and straw brick wall. Results show that environmental cost of straw brick wall is lowest in whole life cycle, and environmental impact is the smallest.