Mid-sized and small businesses often have few resources with an unsteady foundation. Therefore, they tend to encounter more risks and challenges in operation and management, relative to large corporations. As a result, most countries have policies to help the development of mid-sized and small businesses. One of them is the credit guarantee system, providing these businesses one of the basic financing mechanisms. The credit guarantee system in Taiwan is still immature. This study examines credit guarantee systems across countries. First, it summarizes the characteristics of various credit guarantee organizations, their funding sources, their cooperative relationship with banks, the strategies in controlling risks, and the operating mechanisms. Next, it compares the weaknesses and advantages between the guarantee system in Taiwan and other countries. Finally, based on the experience of other countries, it provides suggestions for improving the system in Taiwan, and hopes to enhance its functions in order to provide better and more efficient financing services for the mid-sized and small businesses.