Energy science can be divided into ‘hard energy science(HES)’ and ‘soft energy science(SES)’.  SES is a cross-science that can optimize resources allocation and improve energy utilization. The definition and science nature of SES was discussed.  Research framework of main 10 branch reaearch areas as Energy Economics, Energy Technical Economics, Energy System Engineering, Energy Environmental Science, Energy Law, Energy Financial Engineering, The Strategics of Energy, The Geopolitics of Energy, Corporate Energy Management, Energy Urbanology are given.  The suggestions about SES development are also put forward.