Abstract: Masterbatch M1 of nano-organ-montmorillonite (OMMT)/polyamide-6(PA6) and masterbatch M2 of OMMT/polypropylene(PP) were prepared by melt-extruding method, and nano-OMMT/PA6-PP composites with different OMMT content were prepared with two masterbatches by melt-compound blending with PA6-PP, the composites with the same mass ratio were also prepared by direct blending method. The distribution of OMMT and morphology of the PP disperse phase in composites were characterized by TEM and SEM, and the mechanical properties of nano-OMMT/PA6-PP composites prepared by three processes were also compared. It was found that the OMMT selectively located in PA6 matrix by three processes, and the OMMT shows the best distribution in the composites prepared by the process of M1 masterbatch. The particle size and polydispersity of the PP disperse phase first reduce and then change little with increasing the OMMT content. When the mass ratio of OMMT to PA6-PP is 5∶100, the particle size is minimized and the distribution shows the best. The composites prepared by the processes of masterbatches display smaller disperse phase size and better distribution than that prepared by direct blending. OMMT improvs the flexural modulus, in which the compsites prepared by the process of M1 masterbatch display the highest tensile strength and flexural modulus, and the ones prepared by the process of M2 masterbatch show the best impact toughness.