This chapter aims to explore what subjects have been addressed in green technology innovation (GTI) in China and initiate a journey for the next generation of sustainable-oriented research. Thus, the work examined the literatures enlisted in the database of China National Knowledge Infrastructure (CNKI) on the topics of GTI from 1994 to 2019. Some critical discussion and conclusion are sighted as follows: (1) the research of GTI in China is getting mature compared to the energy-innovation related topics and the researches 10 years ago. It is becoming a dominated research subject. (2) The qualitative publications dominates the researches, the empirical researches are in a shortage. (3) The research subjects are multi-perspective and multi-disciplinary, covering environment science, management, energy and fuels, economics and social behavior. New vibrancy of advanced theoretical and methodological research is particularly needed. (4) The trend of green technology research appears an interdisciplinary research with the themes related to environmental subject, science technology, business economics, engineering and energy & fuels. (5) Different policy implementations have different effects due to the cost structure and maturity of renewable energy. (6) GTI cannot be isolated from the policy or regulation regime, and is becoming a new underpin of current sustainable development in China.

Urban ecosystem has become a critical part of ecological security and draws much attention worldwide. It is both a result of natural ecological system development, and also an inevitable outcome of human ecological system development within a certain stage, with the objective of identifying the possible improvement space for unban ecological security evaluation from complex system perspective. Based on the brittle structure model and set pair theory, this paper firstly explored the main research methods of urban ecological security theory and its characteristics, then conducted a theory of complex system brittleness to analyze the urban ecological security brittle factors, brittle primitives, and brittle structure. Furthermore, it conducted a model of urban ecological system brittleness correlation entropy together with a set pair analysis method to discuss its brittleness. And finally, an ecological safety evaluation has been presented based on the empirical case in Chengdu City of China. The theoretical and empirical analysis shows that the brittle correlation entropy of natural subsystem in urban ecological security is the biggest one. The risks from natural subsystem collapse can easily trigger the brittleness of the entire urban system. The corresponding maximum brittle fluctuation entropy is from economic subsystem; it has a largest impact on the entropy change of urban ecosystem. The way of reducing the uncertainty of urban ecological risks is to lower difference degree coefficient in the system. Relevant decision makers should consider to reduce the increasing degree of entropy and eliminate the fluctuation of the brittle factors. Thus, the threats or risks of urban ecological system can be within the acceptable range and under control. An integrated system management combing with brittleness characters of natural, economics, and social subsystem is necessary. It is helpful for the ecological security construction.