There is a close correlation between physics and engineering technology, and the relationship between physics and energy engineering is a typical example. Applied physics could make significant contribution to China's energy development.This article discusses some energy problems, such as nuclear physics and unclear energy (including fission and fusion energy) , photoeffect and photovoltaic electricity, physics and wind/bio - mass energy, physicsal chemistry and clean coal technology, and geophysics and energy resource exploration. The article also discusses three applications of physics in energy saving in fields of illumination, building and transportation. Finally, the article analyses the prospects of energy sustainable development in China.