Financial stability is fundamental to national economic development, and countries generally recognize the far-reaching impact of the external financial environment on national financial systems and, therefore, actively participate in international financial institutions to jointly maintain global financial stability. This chapter systematically analyzes the role of international financial stability on regional development, balance-of-payments deficits and trade wars, the impact of the global financial crisis on developing countries, and the modern financial system and its evolution process from the following four perspectives to provide a comprehensive picture of the relationship between the balance of payments, financial stability, and regional development. The objectives of this chapter are as follows: 1. To master the role of international financial stability on regional development. 2. To understand the balance of payment deficits and trade wars. 3. To become familiar with financial system reform and policies to promote regional development.