This paper discusses the importance and application prospect of energy-saving and emission-reduction technology combining energy, power and mechanical engineering in the current energy and environment fields. Firstly, the concept of integration of energy power and mechanical engineering and its significance in energy saving and emission reduction are introduced, and the important role of this technology in realizing sustainable development and meeting the challenge of climate change is emphatically expounded. Subsequently, the application practice of this technology in industrial production, construction, transportation and other fields is analyzed, and its remarkable effects in energy saving and emission reduction are summarized. This paper further discusses the important role of technological innovation and policy support in promoting the development of this technology, and emphasizes the importance of interdisciplinary cooperation and exchange in the process of technology popularization and application. Finally, the future research direction and development trend are prospected, and all parties are called upon to make joint efforts to promote the energy-saving and emission-reduction technology integrating energy, power and mechanical engineering to be more widely applied and popularized around the world, so as to contribute to building a clean, low-carbon and sustainable energy future.