Fuzzy control for improving the performance of hybrid power application is presented. The hybrid power system consists of battery and ultracapacitor (UC). It can be expected that the improvement of system efficiency and the long duration period of the energy storage can be achieved by using battery as a main storage and UC as an auxiliary source. UC are electrical energy storage devices which have dynamics features of high power density, very fast power recycling capability and have mechanical robustness. In a short term power applications, this type of energy storage system is widely used for improving power consumption especially when charge and discharge time recovery are critical. However the voltage offer by UC is depending on their operating condition. Thus a power dc-dc converter is required as well as high dynamics control technique should be selected to get the best operating of UC. Therefore in this paper the new fuzzy control technique is being used to control the power flow of UC to supply the transient power demand for a proposed hybrid system. The bidirectional DC-DC converter is used to connect the UC with the battery for the controlled instantaneous electric power flow. The proposed control technique applied in this hybrid system has been verified by the simulation during various condition of the load.