The effects of applying 1-3 vol. % of Multi-walled carbon nanotubes (MWCNTs) to Polypropylen (PP)/Polyamide 6 (PA6) (40/60 vol. /vol.) blend, on rheology of resulted nanocomposites was studied. Samples were prepared via melt mixing using an internal mixer. Viscosity curves of the neat blend showed a plateau at low frequencies. By introducing and increasing the amount of CNTs in the blend, this plateau vanished, the slopes of the curves increased, and a viscosity upturn was observed. This behavior is usually attributed to the existence of a percolated network in polymer matrices. The storage modulus increased at higher nanotube contents, and slopes of the curves tend rapidly toward zero and become independent of the frequency at higher particle loadings. This phenomenon could also be explained by the existence of a mechanically percolated network because of the interactions between the polymer matrices and the tubes. All of PP/PA6 blends nanocomposite samples containing different amount of MWCNTs, exhibited two obvious plateaus of storage modulus, one of them at low frequencies (less than 1 1/sec), which is characteristic of a solid-like rheological behavior. Another plateau which is seen at higher frequencies (about 1-5 1/sec), seems to show the rheological behavior of the interface region. The linear viscoelastic behavior of the blends was discussed using the Fractional Zener Model (FZM) too and the results of applying this model was compared with the experimental data of rheological behavior. The FZM model confirmed the rheological behavior of samples which was attributed to formation of a solid-like structure at low frequencies, but this model could not predict the rheological behavior of interphase. Keywords: Polypropylene, Polyamide 6, Blend Nanocomposite, Rheology, Fractional Zener Model (FZM)