China's economic interaction with the world economy has been significantly strengthened through a system of two-way feedback. In the context of economic globalization and economic interdependence, how can Chinese policies be better coordinated with those of other countries, and how can China fully embrace the role of bilateral and multilateral power? What is the interaction mechanism and transmission of the Chinese business cycle in relation to the global business cycle, and what are the resulting policy implications? The first paper investigates the evolution and nature of macroeconomic interdependence between China and other major players in the world economy in order to analyze China's global economic role and aims to answer these questions theoretically and empirically. The decoupling debate is popular in the field of economics. The aim of the second study is to discover whether there has been decoupling or convergence of business cycles, through various trade channels. The aim of the third paper is to design a framework to study the mechanism of regional monetary cooperation in four regions of China across straits (Mainland China, Hong Kong, Macau, and Taiwan).