The invention relates to a differential grinding roller type rapid biomass catalytic pyrolysis device and method. The device comprises a hopper, a feed system, a differential grinding roller type pyrolysis reactor, a gas-solid separation system, a pyrolysis gas condensation system, a bio-oil collection tank, a carbon collection box, a combustion system, a heat exchange system and a fused salt circulation system. The differential grinding roller type pyrolysis reactor comprises a pair of differential grinding rollers, a closed casing, a high-temperature fused salt heat exchange tube, a materialinlet/outlet, a gas outlet, a drive and transmission device and a thermal insulation system. The pretreated biomass raw materials are subjected to heating and shearing friction of cross high-temperature millstones, the surface carbon residues are continuously peeled off, and effective catalytic pyrolysis inside raw material particles is ensured; the pyrolysis gas is rapidly condensed after gas-solid separation so as to obtain high-grade bio-oil fuel or bio-oil enriched in specific high value-added products; meanwhile, the combustible gas and coke are collected and combusted to produce high temperature flue gas, and the flue gas is used for heating the fused salt and conducting heat and further heating the millstone, so that a self-heating pyrolysis process is realized.