In the context of sustainable development, Internet technology offers new ideas and approaches for promoting pro-environmental behaviour (PEB) in citizens. Utilising data from the 2021 Chinese General Social Survey, the present study employs ordinary least squares regression and mediation analysis to examine the relationships among Internet use, environmental concern, and PEB. The findings reveal a significant positive correlation between Internet use and PEB, with environmental concern serving as a complete mediator. This correlation remained robust across different model specifications and subsamples. Heterogeneity analysis revealed that the positive effect of Internet use on PEB was significant among high-income individuals, urban residents, and females but not among low-income individuals, rural residents, and males. The study proposes measures to bridge the digital divide in rural areas, encourage and support enterprises to use Internet platforms for green marketing activities and design personalised online training courses tailored to the needs of different socio-economic groups. The findings of the present study enhance our understanding of the underlying mechanism of the impact of information on changes in PEB in the context of a digital age, and it provides strong academic support for advancing the digital transformation of global environmental governance.