Recently, Stable securing of wood fuel is an issue by increasing demand for woody biomass. In this research, focusing on the use of willow as a fuel for small gasification combined heat and power. Effect of willow and cedar blend on copyrolysis and co-gasification reactivities and on environmental impacts of willow chip fuel manufacturing system were clarified. With the use of thermogravimetry and differential thermal analyzer, blend of willow char and Japanese cedar char resulted that a synergistic effect was observed in the latter half of the reaction. Also, SRPM estimated the instantaneous reactivity with the highest accuracy in the other char gasification reaction rate models. However, SRPM has unsteady term and requires complex fitting. In the future, a proposal of a simple and highly accuracy model is necessary for the willow reactivity estimation.