Abstract-Energy consumption and efficiency is an important basis of a country's energy strategy formulation. Sankey Diagram has been more and more widely applied in energy consumption research as an intuitive tool to demonstrate historical energy consumption. However, the complexity of the drawing nice Sankey diagram becomes the bottleneck limits efficiency of energy researchers. As a result, an urgent demand has been derived for a graphics software that is able to automatically generate Energy Sankey Diagram based on Energy Balance Table. This paper studies drawing Energy Sankey Diagram based on Java Graphics2D, and introduces a multi arc seamless bonding curve drawing method. Experiments show that the method can not only flexibly generate flow curves, but also reduce the crosses between curves and thus makes diagrams clear and precise.