A nanoparticle continuous-coating device based on spatial atomic layer deposition. A first-stage pipeline unit, a second-stage pipeline unit, a third-stage pipeline unit and a fourth-stage pipeline unit which are connected sequentially. The first-stage pipeline unit is used for providing a first precursor and enabling the first precursor to be adsorbed on surfaces of nanoparticles. The third-stage pipeline unit is used for providing a second precursor and enabling the second precursor to react with the first precursor on the surfaces of the nanoparticles, so that a monomolecular thin film layer is generated on the surfaces of the nanoparticles. The second-stage and fourth-stage pipeline units are used for cleaning the nanoparticles and discharging the redundant first precursor, the redundant second precursor or reaction by-products.