Solar energy as a traditional and emerging energy has been great developed in recent years. It has the features of huge reserves, clean, harmlessness which draw the world attention. Imagine if the successful application of solar energy resources in the modern Public buildings will play a great role in reducing their energy consumption levels. This article analyzes the state of office building energy consumption and energy saving way to discuss the application of solar energy technology in the overall design of Public buildings, to mainly discuss the relationship of the overall pattern of office building and the changes of solar radiation. By mathematical analysis methods to target to the questions such as the choice of office building site, shape coefficient one by one, as the fundamental basis for design.