The invention provides a method for utilizing hydrothermal carbonization for preparing biomass barbecuing charcoal. The method is characterized by comprising the following step one of hydrothermal carbonization reaction, wherein a biomass raw material is any one of wood flour, cotton stalks, rice hulls and coconut shells, the biomass raw material and water are placed into a reaction vessel according to the mass ratio of 1: (4-12), inert gas is introduced, the hydrothermal carbonization reaction is carried out on the anoxic condition, reaction temperature ranges from 250 DEG C to 450 DEG C, reaction pressure ranges from 4 Mpa to 5 Mpa, and reaction time ranges from 20 min to 40 min, so that carbonized biomass mixed liquid is obtained; the step two of solid and liquid separation, wherein the carbonized mixed liquid is separated by utilizing a filtering device for obtaining a carbonized substance; the step three of crushing and screening, wherein the carbonized substance is crushed and screened to obtain charcoal particles with the particle size smaller than 0.5 mm; the step four of compressing and forming, wherein the carbonized substance is formed in a hot-pressed mode, so that the biomass barbecuing charcoal is obtained.