After the financial tsunami in 2008, people are looking forward to the emergence of new economic theories to make up for the structural deficiencies of the mainstream theories and to reveal the economic laws behind complex phenomena. Transactional economics is a brand-new theory emerging in this context. Transaction economics is based on limited rationality, starting from the concept of transaction and organizing itself around transaction networks. It offers a complete reconstruction of economic theory centered on how transaction systems evolve over time. Using this revolutionary theory, the author reveals with a fresh perspective the economic logic behind such peculiar phenomena as the animal instinct of stock investors, economic stagflation, community poverty, and gambling behavior. The insights are truly refreshing. In mainstream economics, economic growth is the result of a synthesis of the economic activities of households and enterprises. Based on this perception, most economic policies start with stimulating transactional agents. Transactional economics argues that economic growth is the product of a self-organizing network of households and firms, rather than a simple superposition of the behavior of transactional agents. In terms of policy design, transaction economics focuses on maintaining the structural integrity of the transaction network and the stability of the cycle. In the face of the impact of the COVID-19 pandemic that lasted three years, corporate balance sheets have been severely damaged and household cash flows have shrunk dramatically. In this situation, the top priority of macro policy is not to stimulate consumption, but to provide direct relief to pivotal enterprises in transaction networks, and to effectively stimulate the vitality of the transaction system through the penetration function of the transaction network. Within the framework of limited rationality, transaction economics has proved the positive feedback mechanism of the evolution of the transaction potential, concluded that the evolution of the transaction system will inevitably lead to polarization, identified the root cause of the collapse of the traditional social cyclical structure, and provided the theoretical basis for the optimization of the modern social system.