Fuel cell (FC)/lithium-ion battery hybrid power system (HPS) gradually becomes a powerful energy source in the future. This paper presents a digital boost converter for FC current regulation in the HPS with a dual-battery energy storage unit (ESU). The digital boost converter regulates the FC current in order to control the FC power generation. Simulations have been conducted in PSIM environment, and the digital controller is implemented with a Microchip dsPIC33FJ06GS202 16- bit microcontroller. Experimental results show that the efficiency of power conversion can reach to 85%.