The invention discloses compound biomass fuel containing sepiolite as well as a preparation method of the fuel. The compound biomass fuel containing the sepiolite comprises components in parts by dry weight as follows: 40-70 parts of agricultural and forestry residues, 10-20 parts of humus layer soil, 20-40 parts of waste tire rubber and 10-20 parts of a compound combustion improver; the compound combustion improver comprises components in parts by weight as follows: 80-120 parts of sepiolite powder, 10-20 parts of basic cupric carbonate, 10-20 parts of coal slime, 10-20 parts of sodium nitrate, 20-30 parts of black shale and 3-7 parts of manganese oxide. The biomass fuel has the high combustion temperature of 1550-1600 DEG C and the combustion efficiency about 40% higher than that of common biomass fuel; the calorific value can reach 4900-5300 kcal/kg, and 1 ton of biomass fuel is equivalent to 0.7 ton of standard coal; combustion tail gas conforms to related national regulations, the desulfurization rate can reach 98%, and the denitration rate can reach 95%.