Transportability and stability of the direct methanol fuel cell (DMFC) system are more excellent than that of the other fuel cell, and so it is suitable for the electronic device of the 1W-200W grade for carrying. In addition, its energy density is higher than primary and secondary Battery. For such a reason, the study about DMFC system is increasing in long time useable applications such as the field of military electronic for portable. This paper describes and analysis the power management strategy of hybrid power system between fuel cell and Li-ion battery for high energy density and fuel efficiency of the system.