Can exergy be used to reflect the environmental issues of a fuel? This article elaborates if and how exergy can be used to reflect the environmental issues of a fuel, and details the processes for some typical fuels. The results show that the exergy method can be well used to reflect the environmental issues of a fuel. The case studies further show that coal samples (1,324.99-1,437.47 kJ/kg) have higher total environmental impacts than the biomass samples (381.02-1,078.81 kJ/kg), and the environmental impacts are mainly contributed by CO2 (52.72%-99.37%), followed by ash (0.18%-35.93%), SO2 (0%-11.77%) and NO2 (0.16%-8.75%).