Heat and mass balance calculation of biological water gas shift process using Thermococcus Onnurineus NA1 was conducted in this study by process simulation. NA1 is a kind of ocean microorganism, was founded 1,650 below sea level, in hydrothermal vents near Papua New Guinea in 2002. In this study, process simulation for biological water gas shift process using NA1 was executed. LDG from steel mill plant and syngas from coal gasification plant was the feed gas of the biological water gas shift process using NA1. The capacity of process was 10,000 ton of hydrogen production per year. CO conversion efficiency of both cases is over 98%.