Input-output analysis is probably the most practical tool of economic analysis. It is the main tool to help us answer three key questions that pertain to the whole economic system. In terms of efficiency and productivity growth, what's the performance of an economy? What is the comparative advantage of an economy compared with the rest of the world? How do policies and measures affect the whole economic system when environmental constrains are taken into account? Of course, many other interesting questions can be posed. The first three chapters in this book introduce three important practices of input-output analysis in China in the fields of water shadow price evaluating and predicting, building energy efficiency impacts evaluating, unfair importation impacts calculating. The last chapter is the advanced research in nonlinear input-output model. The methods and results are quite general, and this feature facilitates the use of the book as a reference source, particularly by applied economists and macro economic managers.