As information and communication technology advances rapidly, real-time live online broadcasting has emerged as a novel social media platform. In particular, live online broadcasts have gained widespread popularity among audiences. However, this process can cause environmental problems. When audiences imitate live content and perform similar field activities, it can have a negative effect on the environment. In this study, an extended theory of planned behavior (TPB) was used to explore how online live broadcasts relate to environmental damage from the perspective of human behavior. A total of 603 valid responses were collected from a questionnaire survey, and a regression analysis was conducted to verify the hypotheses. The findings showed that the TPB can be applied to account for the formation mechanism of behavioral intention of field activities caused by online live broadcasts. The mediating effect of imitation was verified using the above relationship. These findings are expected to provide a practical reference for the control of online live broadcast content and guidance on public environmental behavior.