The invention provides rural residue solid pellet fuel and a preparation method thereof. The rural residue solid pellet fuel is prepared from 80-120 parts of straw, 50-90 parts of wood, 8-15 parts ofagricultural sludge, 40-80 parts of biogas residues, 8-12 parts of calcium carbide waste residue and 4-7 parts of white ash. The problems about pollution to the environment and waste of biomass resources due to random burning of rural straw and wood are solved, the problem of treatment of pathogenic bacteria and pathogenic factors harmful to human in rural sludge is also solved, the solid pellet fuel is prepared from biogas residues, a large amount of undegraded organic matter in the biogas residues is sufficiently utilized, and the energy recovery rate is increased.