A kind of magnetoresistance material was prepared, named as magnetorheological gel (MRG). The MRG samples were fabricated by dispersing carbonyl iron particles (CIP) into the polyurethane gel, and several experimental devices were prepared to investigate the magnetoresistance characteristics of MRG. The magnetoresistance characteristic was systematically tested and the influence of the magnetic field was analyzed. It is found that the resistance value of MRG with the CIP content of 70 wt % can be decreased from 7.56 to 2.44 M Omega with increasing of magnetic field from 0.1 T to 1 T. The experimental results have also proved that CIP content and the composition of matrix have a greater impact on the magnetoresistance characteristics. Because of the interaction between the magnetic force of CIP and motion resistance under a magnetic field, the obvious hysteresis phenomenon was observed and recorded. Lastly, it was observed that the magnetoresistance can be changed reversibly by controlling the magnetic field.