This paper identifies several key differences between ecological economics and conventional economics. From the analysis of basic vision in conventional economics and ecological economics, the paper points outs the serious flaws of conventional economics, which ignore the natural resources and identifies the role the natural capital plays in it. Ecological economics has key distinction for the nature of the resource, and further more the difference between entropy flow and value stream flow.Ecological Economics also stresses the basis of the throughput control to improve the quality of goods and services, thereby enhancing human welfare. As a result three key issues of ecological economics are derived, i,e. the scale relative to ecosystem,wealth or resources distribution and allocation efficiency. Their priority will decrease sequentially. 