The recognition of nanoparticles by imprinted materials via entropic depletion attraction is investigated by dissipative particle dynamics simulations. It is found that the depletion attraction exits between nanoparticles and imprinted materials with complementary shapes based on the interaction energy U(H) and association energy Ea. The strength of the attractive depletion grows with increasing size of a perfectly matched target/cavity (TC) pair owing to the increment in their overlapping excluded volumes. The uptake of targets can be significantly enhanced by increasing the concentration of depletant øD. The selective recognition between perfectly matched and mismatched TC pairs is also studied, and a very high selectivity can be achieved at an optimal øD. The kinetics of the recognition process reveals that small nanoparticles migrate fast and access the cavity easily but move out of the cavities eventually due to their weak association energy. Finally, the synergetic effect of entropic depletion and enthalpic affinity is proved to enhance the association fraction substantially for small perfectly matched TC pairs with weak affinity. Our simulation results demonstrate the importance of the depletion effect on the nanoparticle-imprinting technology.