Environmental awareness and behavior play a crucial role in the improvement of the environment. Five dimensions of environmental awareness are considered here including environmental values, environmental knowledge, environmental responsibility, environmental ability and environmental concern while we also distinguish between private and public environmental behaviors. Based on data from the China General Social Survey (CGSS) in 2003, 2010 and 2021, this research investigated changes in Chinese residents’ environmental awareness and environmental behavior and the relationship between them. The relevant empirical methods were the MV-Probit model, the Poisson model and a mediating effect model. The results are as follows: (1) From 2003 to 2021, environmental awareness of the public has improved significantly. Among them, environmental values, environmental knowledge and environmental concern have increased by 24.5%, 12.6% and 12.77%, respectively, while environmental capacity has decreased by 7.27% from 2010 to 2021. The eastern region of China has the highest score of environmental awareness, while the western region has the lowest one. (2) From 2003 to 2021, the public’s green consumption behavior changed from more than half of the public never consuming green products in 2003 to nearly 75% always or often consuming green products in 2021. Increases in recycling were also found over time. However, the participation rate in public environmental behavior declined. In 2021, environmental behaviors were lowest in the eastern region and highest in the western region. (3) Environmental responsibility, environmental concern and environmental capacity direct and indirectly affect private and public environmental behaviors and the number of environmental behaviors through the willingness to protect the environment, which plays a semi-mediating role. Environmental knowledge only has a direct impact on private green consumption behavior. (4) There is a correlation between public and private environmental behaviors. Given the results of this study, a series of policy implications and recommendations are provided.