The invention discloses a sliding automatic feeding device of a biomass furnace. The sliding automatic feeding device comprises a device body, a feeder and a discharger. Through the principle of a slider-crank mechanism, rotating of a feeding motor shaft is converted into sliding of the feeder, the function of automatic feeding is achieved, and the labor intensity is reduced; meanwhile, through sliding of the feeder, coking materials generated after biomass fuel is combusted can be pushed to an ash falling opening from a combustion plate, the function of removing the coking materials is achieved, and it is guaranteed that the biomass fuel is combusted sufficiently; and through the innovatively-designed device body and feeder, the biomass fuel can bear the dual functions of lateral wind andbottom wind, and combustion is more sufficient.