Abstract: Blends of polyamide 11 and phosphorus-nitrogen intumescent (IFR) containing flame retardant modifier were prepared on an internal mixer by melt compounding, and their dynamic rheological and mechanical properties were investigated using a rotational rheometer and dynamic mechanical analyzer. Melt of both polyamid 11 and its modifier were pseudoplastic fluid and exhibited shear-thinning.The storage modulus,loss modulus, and complex viscosity of the blends were decreased with increasing IFR contents, the phase separation did not occur in the blends. The storage modulus of the glassy blends was enhanced with the increasing IFR loading level.