The nano-hybrid pour point depressants (PPDs) was prepared by organically modified nano-clay covering in polymeric PPDs, namely, polymethyl acrylate (PMA), ethylene vinyl acetate copolymer and poly-a olefin. The effects of nano-hybrid PPDs on the cold flow properties of diesel fuel were evaluated. The crystal morphology and crystallization behavior of the diesel fuels in low-temperature were also observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The results indicated that the nano-hybrid PPDs always exhibited a better cold filter plugging point, while it had little effect on solidifying point compared to pure PPDs, and PMA hybrid with organically modified nano-clay in mass ratio of 4:1 exerted the best depression effect. Up addition of 0.15 wt.% nano-hybrid PMA (4:1) in diesel, the cold filter plugging point and solidifying point were reduced by 16 degrees C and 14 degrees C, respectively. DSC and POM results showed that the nano-hybrid PMA involved heterogeneous nucleation activity. The nano hybrid PMA modified the crystallization behavior of diesel by transforming the shape of wax crystals and inhibiting the formation of larger crystals, which result in compact, regular, tiny particle-shaped and uniform arrangement wax morphologies. (C) 2016 Elsevier Ltd. All rights reserved.