In order to investigate the normal force behavior of Magnetorheological Grease（MRG），three magnetorheological greases with carbonyl iron powder mass fractions of 30%，50% and 70% respectively were fabricated and measured by using a rotational rheometer in the mode of oscillatory shear. And the effects of magnetic field，time，strain amplitude，frequency and temperature on the normal force were systematically analyzed. The results show that the normal force values of three MRG samples increase with the increase of magnetic field strength. When the magnetic field strength is 740 kA/m，the maximum value of each sample reaches 6.97 N，8.93 N，14.91 N. Under different magnetic field levels，the influence of time on the normal force of magnetorheological grease undergoes three stages of slight decrease，constant，and slowly increasing. In the entire frequency range，the normal force value of the MRG with different magnetic field strengths changes slightly and basically at a stable value. There is a strain critical value，and the normal force increases with the strain amplitude at a faster speed before the critical value，further increases the strain amplitude and decreases the growth rate after exceeding the critical value. In addition，the normal force of the three MRG samples increases with increasing temperature and the MRG-70 normal force value is the largest. The above study of normal force in MRG is the theoretical basis for the design，optimization and application of magnetorheological grease devices.