The rheological properties of magnetorheological fluid at the damping channel was studied.The COMSOL, Fluent were used to simulate fluid properties and the velocity, pressure distribution of magnetorheological fluid at the damping channel were analyzed. The results show that the annular groove can effectively improve damper damping force, and the damping force of the damper can achieve maximum when the depth is 055 mm, the width is 22 mm, the gap is 14 mm, also proves the theoretical model is correct.