As improving energy efficiency and increasing energy R&D investment may be the main means for China's industrial sector to achieve sustainable growth, this book attempts to unify energy use efficiency and energy R&D inputs into a standardized economic analysis framework. By distinguishing between energy R&D inputs and non-energy R&D inputs, this book draws on the research paradigm of neoclassical economics to clarify the basic concepts and endogenous mechanisms of energy-saving technological progress as a logical starting point. Under the framework of the existing endogenous growth theory analysis, the heterogeneous R&D inputs are divided into two different mechanisms that affect energy use efficiency, namely factor substitution effect and energy-efficient input increase effect, and a heterogeneous R&D input is constructed. This book constructed an analytical framework for endogenous energy-saving technological progress in the industrial sector based on heterogeneous R&D inputs; it established a mathematical model for the endogenous energy-saving technological advancement of the industrial sector based on heterogeneous R&D inputs; it estimated the energy-saving technological progress rate of 37 Chinese industrial sub-sectors from 1980 to 2010; fourth, it has empirically examined the relationship between the heterogeneous R&D investment in China's industrial sector and its energy-saving technological advancement rate.