Biomass is an important energy source to create a more sustainable society. But, the biomass has some disadvantages as a fuel, because of its low calorific value, high moisture content and large volume causing logistics issues. So, the biomass needs modifications for upgrading in industrial or domestic applications. Torrefaction is a thermal treatment step in the relatively low temperature range of 200-300℃, which aims to obtain a much better fuel quality for combustion applications. Biomass partly decomposes giving off water and various types of volatiles during the process, which resulted in the loss of mass and energy as well as a reduction of water content and increasement of calorific value of the main product, torrefied biomass. And the torrefaction process is combined with pelletization process for densification of torrefied biomass, which makes it economically feasible with an effect of lowering transportation cost as well as the fuel price increasement. In this paper, characterization of biomass, basic concept of torrefaction, equipments & processes of torrefaction and current status of commercialization were discussed.