Polyolefins have significantly obtained a main position in our daily life and their consumption is continuously increasing, which leads to grow environmental pollution. To overcome this problem, production of degradable and biodegradable polyolefins is going to be much more important. In the present work, blends of high density polyethylene (HDPE) and water-free thermoplastic starch (TPS) containing linear low density polyethylene-grafted-maleic anhydride (LLDPE-g-MA) as a compatibilizer were prepared with various TPS contents. The complete gelatinization achieved in the end of the mixing of starch and glycerol (30% wt.), which was confirmed by X-ray diffraction. Rheological behavior of the blends was measured by RMS (oscillation and rotational mode) and Capillary Rheometer. The storage modulus results showed a nonterminal behavior which can be related to formation of a three dimensional network of TPS droplets at high TPS concentration. Inflexible segments of TPS provided high viscoelastic droplets as a disperse phase. Interaction between TPS and HDPE reduces mobility of HDPE chains which probably exist in interfacial region at the presence of compatiblizer. In other hand, existence of the network strongly boost the mobility reduction, which was also can confirmed by the upturn region of shear viscosity in low shear rate. The results also showed that the blend properties extensively depend on the network shape and stability which was controlled by shear rate in the twin screw extruder. All Rheological data was confirmed by SEM micrographs. Keywords: Rheological behavior, HDPE/TPS, Biodegradable