During the last two decades, environmental concerns and a tendency towards elimination of mineral reinforcing component in polymer composites have resulted in creation of the new types of composite materials known as polymer-polymer composite. Microfibrillar composites are a kind of polymer-polymer fiber composites in which polymeric fibers create in-situ in the polymer matrix. Due to low density, easy processing, reasonable price and no need for fiber distribution in the matrix, microfibrillar composites have attracted the attention of researchers . Microfibrillar composite can be made by polypropylene and polyamide6 because these polymers are thermodynamically immiscible and there is a great difference in their melting point. In this study, Polypropylene, Polyamide6 and Polypropylene grafted with maleic anhydride (as compatibilizer) have been entered to the single screw extruder with the temperature profile 190-220-240-250 °C and 80 rpm to create fibrillar morphology; the output blends of the extruder were drawn with draw ratios 3, 5 and 8. The compression molding at 190° C and 100 bar pressure has been applied to prepare the final microfibrillar composite. The results of the rheological tests (RMS) and melt flow index indicated that the storage and loss modulus and the complex viscosity of the microfibrillar composite increased by increasing of Polyamide6 composition, but the melt flow index decreased. Moreover, by increasing the draw ratio from 3 to 5, the storage modulus, loss modulus and complex viscosity increased but the melt flow index decreased and then by increasing the draw ratio from 5 to 8, the storage modulus, loss modulus and complex viscosity decreased. In order to evaluate the effect of compatibilizer on the rheology of microfibrillar composites, RMS, melt flow index and capillary rheometer tests was conducted on samples with and without compatibilizer. The results of the tests showed that the presence of compatibilizer (PP-g-MAH) reduced the storage modulus, loss modulus and complex viscosity and increase the melt flow index. The results of mechanical tests on samples made with different draw ratios showed that by increasing the draw ratio from 3 to 5, the mechanical properties (tensile strength, young modulus and elongation at break) increased but by increasing the draw ratio from 5 to 8, the decreasing of mechanical properties was observed. By increasing Polyamide6 composition, at first the tensile strength of compatible microfibrillar composite increased but by enhancing the Polyamide6 phase due to an increase weak interface in the composite structure, this amount decreased. Applying 5wt% compatibilizer resulted in enhancement of the mechanical properties compare to incompatible samples, but by increasing the amount of PP-g-MAH to 10wt% due to weak mechanical properties of PP-g-MAH, the mechanical properties decreased. Finally, the Scanning electron microscope images showed that the presence of compatibilizer in microfibrillar composites reduce the number of undeform droplets and the diameter of microfibrils. On the other hand, by increasing the draw ratio from 3 to 5, the microfibrils’s diameter strongly decreased, but by increasing the draw ratio from 5 to 8, the microfibrils’s diameter increased. Furthermore, the images of the scanning electron microscope showed that by increasing the phase composition of Polyamide6 in microfibrillar composites, the average diameters of microfibrils will be increased. Keywords: Microfibrillar composite, polypropylene, polyamide6, PP-g-MAH