Attempts have been made to prepare thermoplastic elastomers based on polyethylene and silicone rubber by thermomechanical reactive mixing of the two polymers. Occurrence of both grafting and vulcanization of the silicone rubber chains was evidenced by increase in the mixing torque, solvent extraction data, as well as FTIR and DSC analysis. Among different types of polyethylene, linear low-density polyethylene (LLDPE) showed higher potential to promote reactions between the two phases. The blend based on LLDPE prepared at high temperature and shear rate exhibited distinct rheological behavior with a non-Newtonian characteristic and higher dynamic viscosity measured by rheomechanical spectroscopy (RMS) than the two individual components at low frequencies.