Covid-19 has accelerated the process of digital transformation of the global society，and the problems of energy consumption and greenhouse effect have also attracted the attention of all countries. Against the background of promoting sustainable development，Japan，South Korea and Singapore are facing energy and environmental problems of different degrees respectively，and have carried out various explorations on building a sustainable society. Their digital means assist society in progressing towards a more energy and environment friendly direction. This paper summarizes the energy and environmental sustainable development measures of these three countries，and proposes four suggestions for China’s digitalization to promote energy and environmental sustainable development：designing a unified dispatching system for multiple energy sources based on digital twin technology，improving the intelligence of public transportation，cultivating the digital transformation of energy smart cities under the advantages of location，and establish a green smart city with unified energy management.