When a public crisis such as COVID-19 occurs, factors that affect health-related behaviors, such as compliance with safety precautions, health professionals, and directives from government agencies will become more obvious. This research explores the differences between the people of the United States and China regarding preventive behavioral intentions, perceptions of personal and social risks, seriousness, and other cultural characteristics in the context of the COVID-19 health crisis. The purpose is to provide insights that can be used when global public health events occur in the future. A total of 536 people who lived in the US and China from 12 July to 7 September 2020 were recruited in the survey. Through a web-based survey, differences in the attitudes and perceptions of COVID-19 between the two countries were identified. Overall, the people of China scored higher than Americans on several measures regarding personal risk perception, social risk perception, and seriousness. Chinese citizens also had higher preventive behavioral intentions than their US counterparts. In addition, the relationships between cultural dimensions and health-related variables were also different.